[{"data":1,"prerenderedAt":4968},["ShallowReactive",2],{"navigation":3,"chapter-cours-snt-2nde\u002Fsg-photo-numerique":585,"chapter-index-snt-2nde\u002Fsg-photo-numerique":3416,"chapter-memo-snt-2nde\u002Fsg-photo-numerique":3518},[4,224,440],{"title":5,"path":6,"stem":7,"children":8},"SNT — Seconde","\u002Fsnt-2nde","0.snt-2nde\u002F0.index",[9,10,14,36,66,92,118,144,162,184,206],{"title":5,"path":6,"stem":7},{"title":11,"path":12,"stem":13},"REVIEW pédagogique — SNT 2nde","\u002Fsnt-2nde\u002Freview","0.snt-2nde\u002FREVIEW",{"title":15,"path":16,"stem":17,"children":18},"Internet","\u002Fsnt-2nde\u002Fsa-internet","0.snt-2nde\u002Fsa-internet\u002F0.index",[19,20,24,28,32],{"title":15,"path":16,"stem":17},{"title":21,"path":22,"stem":23},"Adresses symboliques et DNS","\u002Fsnt-2nde\u002Fsa-internet\u002Fadresses-dns","0.snt-2nde\u002Fsa-internet\u002F1.adresses-dns",{"title":25,"path":26,"stem":27},"Internet et les réseaux physiques","\u002Fsnt-2nde\u002Fsa-internet\u002Freseaux-physiques","0.snt-2nde\u002Fsa-internet\u002F2.reseaux-physiques",{"title":29,"path":30,"stem":31},"Protocoles TCP\u002FIP et routage des paquets","\u002Fsnt-2nde\u002Fsa-internet\u002Ftcp-ip-routage","0.snt-2nde\u002Fsa-internet\u002F3.tcp-ip-routage",{"title":33,"path":34,"stem":35},"Réseaux pair-à-pair","\u002Fsnt-2nde\u002Fsa-internet\u002Fpair-a-pair","0.snt-2nde\u002Fsa-internet\u002F4.pair-a-pair",{"title":37,"path":38,"stem":39,"children":40},"Le Web","\u002Fsnt-2nde\u002Fsb-web","0.snt-2nde\u002Fsb-web\u002F0.index",[41,42,46,50,54,58,62],{"title":37,"path":38,"stem":39},{"title":43,"path":44,"stem":45},"Histoire du Web","\u002Fsnt-2nde\u002Fsb-web\u002Fhistoire-web","0.snt-2nde\u002Fsb-web\u002F1.histoire-web",{"title":47,"path":48,"stem":49},"URL et hypertexte","\u002Fsnt-2nde\u002Fsb-web\u002Furl-hypertexte","0.snt-2nde\u002Fsb-web\u002F2.url-hypertexte",{"title":51,"path":52,"stem":53},"HTML et CSS — le contenu et la présentation","\u002Fsnt-2nde\u002Fsb-web\u002Fhtml-css","0.snt-2nde\u002Fsb-web\u002F3.html-css",{"title":55,"path":56,"stem":57},"Client-serveur et requêtes HTTP","\u002Fsnt-2nde\u002Fsb-web\u002Fclient-serveur-http","0.snt-2nde\u002Fsb-web\u002F4.client-serveur-http",{"title":59,"path":60,"stem":61},"Moteurs de recherche","\u002Fsnt-2nde\u002Fsb-web\u002Fmoteurs-recherche","0.snt-2nde\u002Fsb-web\u002F5.moteurs-recherche",{"title":63,"path":64,"stem":65},"Sécurité du navigateur et notions juridiques","\u002Fsnt-2nde\u002Fsb-web\u002Fsecurite-droits","0.snt-2nde\u002Fsb-web\u002F6.securite-droits",{"title":67,"path":68,"stem":69,"children":70},"Les réseaux sociaux","\u002Fsnt-2nde\u002Fsc-reseaux-sociaux","0.snt-2nde\u002Fsc-reseaux-sociaux\u002F0.index",[71,72,76,80,84,88],{"title":67,"path":68,"stem":69},{"title":73,"path":74,"stem":75},"Panorama des réseaux sociaux","\u002Fsnt-2nde\u002Fsc-reseaux-sociaux\u002Fpanorama-rs","0.snt-2nde\u002Fsc-reseaux-sociaux\u002F1.panorama-rs",{"title":77,"path":78,"stem":79},"Identité numérique et authentification","\u002Fsnt-2nde\u002Fsc-reseaux-sociaux\u002Fidentite-numerique","0.snt-2nde\u002Fsc-reseaux-sociaux\u002F2.identite-numerique",{"title":81,"path":82,"stem":83},"Le modèle économique des réseaux sociaux","\u002Fsnt-2nde\u002Fsc-reseaux-sociaux\u002Fmodele-economique","0.snt-2nde\u002Fsc-reseaux-sociaux\u002F3.modele-economique",{"title":85,"path":86,"stem":87},"Petit monde et graphes","\u002Fsnt-2nde\u002Fsc-reseaux-sociaux\u002Fpetit-monde-graphes","0.snt-2nde\u002Fsc-reseaux-sociaux\u002F4.petit-monde-graphes",{"title":89,"path":90,"stem":91},"La cyberviolence","\u002Fsnt-2nde\u002Fsc-reseaux-sociaux\u002Fcyberviolence","0.snt-2nde\u002Fsc-reseaux-sociaux\u002F5.cyberviolence",{"title":93,"path":94,"stem":95,"children":96},"Les données structurées et leur traitement","\u002Fsnt-2nde\u002Fsd-donnees-structurees","0.snt-2nde\u002Fsd-donnees-structurees\u002F0.index",[97,98,102,106,110,114],{"title":93,"path":94,"stem":95},{"title":99,"path":100,"stem":101},"Données et formats","\u002Fsnt-2nde\u002Fsd-donnees-structurees\u002Fdonnees-formats","0.snt-2nde\u002Fsd-donnees-structurees\u002F1.donnees-formats",{"title":103,"path":104,"stem":105},"Données structurées","\u002Fsnt-2nde\u002Fsd-donnees-structurees\u002Fdonnees-structurees","0.snt-2nde\u002Fsd-donnees-structurees\u002F2.donnees-structurees",{"title":107,"path":108,"stem":109},"Métadonnées","\u002Fsnt-2nde\u002Fsd-donnees-structurees\u002Fmetadonnees","0.snt-2nde\u002Fsd-donnees-structurees\u002F3.metadonnees",{"title":111,"path":112,"stem":113},"Traitement de tables","\u002Fsnt-2nde\u002Fsd-donnees-structurees\u002Ftraitement-tables","0.snt-2nde\u002Fsd-donnees-structurees\u002F4.traitement-tables",{"title":115,"path":116,"stem":117},"Le cloud","\u002Fsnt-2nde\u002Fsd-donnees-structurees\u002Fcloud","0.snt-2nde\u002Fsd-donnees-structurees\u002F5.cloud",{"title":119,"path":120,"stem":121,"children":122},"Localisation, cartographie et mobilité","\u002Fsnt-2nde\u002Fse-localisation-cartographie","0.snt-2nde\u002Fse-localisation-cartographie\u002F0.index",[123,124,128,132,136,140],{"title":119,"path":120,"stem":121},{"title":125,"path":126,"stem":127},"GPS et Galileo — se situer grâce aux satellites","\u002Fsnt-2nde\u002Fse-localisation-cartographie\u002Fgps-galileo","0.snt-2nde\u002Fse-localisation-cartographie\u002F1.gps-galileo",{"title":129,"path":130,"stem":131},"Décoder une trame NMEA","\u002Fsnt-2nde\u002Fse-localisation-cartographie\u002Ftrame-nmea","0.snt-2nde\u002Fse-localisation-cartographie\u002F2.trame-nmea",{"title":133,"path":134,"stem":135},"Cartes numériques — GeoPortail et OpenStreetMap","\u002Fsnt-2nde\u002Fse-localisation-cartographie\u002Fcartes-numeriques","0.snt-2nde\u002Fse-localisation-cartographie\u002F3.cartes-numeriques",{"title":137,"path":138,"stem":139},"Itinéraires et graphes","\u002Fsnt-2nde\u002Fse-localisation-cartographie\u002Fitineraires-graphes","0.snt-2nde\u002Fse-localisation-cartographie\u002F4.itineraires-graphes",{"title":141,"path":142,"stem":143},"Confidentialité de la position","\u002Fsnt-2nde\u002Fse-localisation-cartographie\u002Fconfidentialite-position","0.snt-2nde\u002Fse-localisation-cartographie\u002F5.confidentialite-position",{"title":145,"path":146,"stem":147,"children":148},"Informatique embarquée et objets connectés","\u002Fsnt-2nde\u002Fsf-info-embarquee","0.snt-2nde\u002Fsf-info-embarquee\u002F0.index",[149,150,154,158],{"title":145,"path":146,"stem":147},{"title":151,"path":152,"stem":153},"Systèmes informatiques embarqués","\u002Fsnt-2nde\u002Fsf-info-embarquee\u002Fsystemes-embarques","0.snt-2nde\u002Fsf-info-embarquee\u002F1.systemes-embarques",{"title":155,"path":156,"stem":157},"Capteurs et actionneurs","\u002Fsnt-2nde\u002Fsf-info-embarquee\u002Fcapteurs-actionneurs","0.snt-2nde\u002Fsf-info-embarquee\u002F2.capteurs-actionneurs",{"title":159,"path":160,"stem":161},"IHM et objets connectés","\u002Fsnt-2nde\u002Fsf-info-embarquee\u002Fihm-objet-connecte","0.snt-2nde\u002Fsf-info-embarquee\u002F3.ihm-objet-connecte",{"title":163,"path":164,"stem":165,"children":166},"Photographie numérique","\u002Fsnt-2nde\u002Fsg-photo-numerique","0.snt-2nde\u002Fsg-photo-numerique\u002F0.index",[167,168,172,176,180],{"title":163,"path":164,"stem":165},{"title":169,"path":170,"stem":171},"Photosites, pixels et résolution","\u002Fsnt-2nde\u002Fsg-photo-numerique\u002Fpixels-resolution","0.snt-2nde\u002Fsg-photo-numerique\u002F1.pixels-resolution",{"title":173,"path":174,"stem":175},"Les algorithmes de l'appareil photo","\u002Fsnt-2nde\u002Fsg-photo-numerique\u002Falgorithmes-photo","0.snt-2nde\u002Fsg-photo-numerique\u002F2.algorithmes-photo",{"title":177,"path":178,"stem":179},"Les métadonnées EXIF","\u002Fsnt-2nde\u002Fsg-photo-numerique\u002Fmetadonnees-exif","0.snt-2nde\u002Fsg-photo-numerique\u002F3.metadonnees-exif",{"title":181,"path":182,"stem":183},"Traiter une image en Python","\u002Fsnt-2nde\u002Fsg-photo-numerique\u002Ftraitement-rgb","0.snt-2nde\u002Fsg-photo-numerique\u002F4.traitement-rgb",{"title":185,"path":186,"stem":187,"children":188},"Notions transversales de programmation","\u002Fsnt-2nde\u002Fsh-prog-notions","0.snt-2nde\u002Fsh-prog-notions\u002F0.index",[189,190,194,198,202],{"title":185,"path":186,"stem":187},{"title":191,"path":192,"stem":193},"Séquences d'instructions et variables","\u002Fsnt-2nde\u002Fsh-prog-notions\u002Fsequences-affectations","0.snt-2nde\u002Fsh-prog-notions\u002F1.sequences-affectations",{"title":195,"path":196,"stem":197},"Instructions conditionnelles","\u002Fsnt-2nde\u002Fsh-prog-notions\u002Fconditionnelles","0.snt-2nde\u002Fsh-prog-notions\u002F2.conditionnelles",{"title":199,"path":200,"stem":201},"Boucles bornées et non bornées","\u002Fsnt-2nde\u002Fsh-prog-notions\u002Fboucles","0.snt-2nde\u002Fsh-prog-notions\u002F3.boucles",{"title":203,"path":204,"stem":205},"Définitions et appels de fonctions","\u002Fsnt-2nde\u002Fsh-prog-notions\u002Ffonctions","0.snt-2nde\u002Fsh-prog-notions\u002F4.fonctions",{"title":207,"path":208,"stem":209,"children":210},"Démo des widgets MDC","\u002Fsnt-2nde\u002Fzz-demo-widgets","0.snt-2nde\u002Fzz-demo-widgets\u002F0.index",[211,212,216,220],{"title":207,"path":208,"stem":209},{"title":213,"path":214,"stem":215},"Démo statique — callouts, code, BO, illustration","\u002Fsnt-2nde\u002Fzz-demo-widgets\u002Fstatique","0.snt-2nde\u002Fzz-demo-widgets\u002F1.statique",{"title":217,"path":218,"stem":219},"Démo interactive — self-eval et python-snippet","\u002Fsnt-2nde\u002Fzz-demo-widgets\u002Finteractif","0.snt-2nde\u002Fzz-demo-widgets\u002F2.interactif",{"title":221,"path":222,"stem":223},"Démo · 14 widgets de manipulation NSI","\u002Fsnt-2nde\u002Fzz-demo-widgets\u002Fwidgets-manipulation","0.snt-2nde\u002Fzz-demo-widgets\u002F3.widgets-manipulation",{"title":225,"path":226,"stem":227,"children":228},"NSI — Première","\u002Fnsi-1ere","1.nsi-1ere\u002F0.index",[229,230,234,256,282,304,328,354,380,410],{"title":225,"path":226,"stem":227},{"title":231,"path":232,"stem":233},"Relecture pédagogique — 8 chapitres NSI 1ère (PA → PH)","\u002Fnsi-1ere\u002Freview","1.nsi-1ere\u002FREVIEW",{"title":235,"path":236,"stem":237,"children":238},"Histoire de l'informatique","\u002Fnsi-1ere\u002Fpa-histoire-info","1.nsi-1ere\u002Fpa-histoire-info\u002F0.index",[239,240,244,248,252],{"title":235,"path":236,"stem":237},{"title":241,"path":242,"stem":243},"De la préantiquité aux machines à calculer","\u002Fnsi-1ere\u002Fpa-histoire-info\u002Fpreantiquite-aux-machines","1.nsi-1ere\u002Fpa-histoire-info\u002F1.preantiquite-aux-machines",{"title":245,"path":246,"stem":247},"La machine universelle (1930-1950)","\u002Fnsi-1ere\u002Fpa-histoire-info\u002Fmachine-universelle","1.nsi-1ere\u002Fpa-histoire-info\u002F2.machine-universelle",{"title":249,"path":250,"stem":251},"Les ordinateurs modernes (1947-1990)","\u002Fnsi-1ere\u002Fpa-histoire-info\u002Fordinateurs-modernes","1.nsi-1ere\u002Fpa-histoire-info\u002F3.ordinateurs-modernes",{"title":253,"path":254,"stem":255},"Réseaux, Web et IA (1969 à aujourd'hui)","\u002Fnsi-1ere\u002Fpa-histoire-info\u002Freseaux-et-web","1.nsi-1ere\u002Fpa-histoire-info\u002F4.reseaux-et-web",{"title":257,"path":258,"stem":259,"children":260},"Représentation des données — types et valeurs","\u002Fnsi-1ere\u002Fpb-types-valeurs","1.nsi-1ere\u002Fpb-types-valeurs\u002F0.index",[261,262,266,270,274,278],{"title":257,"path":258,"stem":259},{"title":263,"path":264,"stem":265},"Bases de numération et entiers positifs","\u002Fnsi-1ere\u002Fpb-types-valeurs\u002Fbases-entiers-positifs","1.nsi-1ere\u002Fpb-types-valeurs\u002F1.bases-entiers-positifs",{"title":267,"path":268,"stem":269},"Entiers relatifs et complément à deux","\u002Fnsi-1ere\u002Fpb-types-valeurs\u002Fentiers-relatifs","1.nsi-1ere\u002Fpb-types-valeurs\u002F2.entiers-relatifs",{"title":271,"path":272,"stem":273},"Nombres flottants et virgule flottante","\u002Fnsi-1ere\u002Fpb-types-valeurs\u002Fflottants","1.nsi-1ere\u002Fpb-types-valeurs\u002F3.flottants",{"title":275,"path":276,"stem":277},"Textes et encodages — ASCII, ISO-8859-1, Unicode","\u002Fnsi-1ere\u002Fpb-types-valeurs\u002Ftextes-encodages","1.nsi-1ere\u002Fpb-types-valeurs\u002F4.textes-encodages",{"title":279,"path":280,"stem":281},"Valeurs booléennes et opérateurs logiques","\u002Fnsi-1ere\u002Fpb-types-valeurs\u002Fbooleens","1.nsi-1ere\u002Fpb-types-valeurs\u002F5.booleens",{"title":283,"path":284,"stem":285,"children":286},"Représentation des données : types construits","\u002Fnsi-1ere\u002Fpc-types-construits","1.nsi-1ere\u002Fpc-types-construits\u002F0.index",[287,288,292,296,300],{"title":283,"path":284,"stem":285},{"title":289,"path":290,"stem":291},"Tableaux et listes","\u002Fnsi-1ere\u002Fpc-types-construits\u002Ftableaux-listes","1.nsi-1ere\u002Fpc-types-construits\u002F1.tableaux-listes",{"title":293,"path":294,"stem":295},"Listes en compréhension","\u002Fnsi-1ere\u002Fpc-types-construits\u002Fcomprehension","1.nsi-1ere\u002Fpc-types-construits\u002F2.comprehension",{"title":297,"path":298,"stem":299},"Tuples et p-uplets nommés","\u002Fnsi-1ere\u002Fpc-types-construits\u002Ftuples","1.nsi-1ere\u002Fpc-types-construits\u002F3.tuples",{"title":301,"path":302,"stem":303},"Dictionnaires","\u002Fnsi-1ere\u002Fpc-types-construits\u002Fdictionnaires","1.nsi-1ere\u002Fpc-types-construits\u002F4.dictionnaires",{"title":305,"path":306,"stem":307,"children":308},"Traitement de données en tables","\u002Fnsi-1ere\u002Fpd-tables-donnees","1.nsi-1ere\u002Fpd-tables-donnees\u002F0.index",[309,310,314,318,322],{"title":305,"path":306,"stem":307},{"title":311,"path":312,"stem":313},"Tables et CSV","\u002Fnsi-1ere\u002Fpd-tables-donnees\u002Ftables-csv","1.nsi-1ere\u002Fpd-tables-donnees\u002F1.tables-csv",{"title":315,"path":316,"stem":317},"Recherche et filtrage","\u002Fnsi-1ere\u002Fpd-tables-donnees\u002Frecherche","1.nsi-1ere\u002Fpd-tables-donnees\u002F2.recherche",{"title":319,"path":320,"stem":321},"Trier une table","\u002Fnsi-1ere\u002Fpd-tables-donnees\u002Ftri","1.nsi-1ere\u002Fpd-tables-donnees\u002F3.tri",{"title":323,"path":324,"stem":325,"children":326},"Fusion et indexation","\u002Fnsi-1ere\u002Fpd-tables-donnees\u002Ffusion-indexation","1.nsi-1ere\u002Fpd-tables-donnees\u002F4.fusion-indexation",[327],{"title":323,"path":324,"stem":325},{"title":329,"path":330,"stem":331,"children":332},"IHM sur le Web","\u002Fnsi-1ere\u002Fpe-ihm-web","1.nsi-1ere\u002Fpe-ihm-web\u002F0.index",[333,334,338,342,346,350],{"title":329,"path":330,"stem":331},{"title":335,"path":336,"stem":337},"HTML et CSS — rappel de structure","\u002Fnsi-1ere\u002Fpe-ihm-web\u002Fhtml-css-bases","1.nsi-1ere\u002Fpe-ihm-web\u002F1.html-css-bases",{"title":339,"path":340,"stem":341},"Formulaires HTML","\u002Fnsi-1ere\u002Fpe-ihm-web\u002Fformulaires","1.nsi-1ere\u002Fpe-ihm-web\u002F2.formulaires",{"title":343,"path":344,"stem":345},"Événements JavaScript","\u002Fnsi-1ere\u002Fpe-ihm-web\u002Fevenements-js","1.nsi-1ere\u002Fpe-ihm-web\u002F3.evenements-js",{"title":347,"path":348,"stem":349},"Manipulation du DOM","\u002Fnsi-1ere\u002Fpe-ihm-web\u002Fdom-interaction","1.nsi-1ere\u002Fpe-ihm-web\u002F4.dom-interaction",{"title":351,"path":352,"stem":353},"Client, serveur et HTTP","\u002Fnsi-1ere\u002Fpe-ihm-web\u002Fclient-serveur-http","1.nsi-1ere\u002Fpe-ihm-web\u002F5.client-serveur-http",{"title":355,"path":356,"stem":357,"children":358},"Architectures matérielles et systèmes d'exploitation","\u002Fnsi-1ere\u002Fpf-archi-os","1.nsi-1ere\u002Fpf-archi-os\u002F0.index",[359,360,364,368,372,376],{"title":355,"path":356,"stem":357},{"title":361,"path":362,"stem":363},"Le modèle de von Neumann","\u002Fnsi-1ere\u002Fpf-archi-os\u002Fvon-neumann","1.nsi-1ere\u002Fpf-archi-os\u002F1.von-neumann",{"title":365,"path":366,"stem":367},"Périphériques et interface homme-machine","\u002Fnsi-1ere\u002Fpf-archi-os\u002Fperipheriques-ihm","1.nsi-1ere\u002Fpf-archi-os\u002F2.peripheriques-ihm",{"title":369,"path":370,"stem":371},"Les systèmes d'exploitation","\u002Fnsi-1ere\u002Fpf-archi-os\u002Fsystemes-exploitation","1.nsi-1ere\u002Fpf-archi-os\u002F3.systemes-exploitation",{"title":373,"path":374,"stem":375},"Linux et le shell","\u002Fnsi-1ere\u002Fpf-archi-os\u002Flinux-shell","1.nsi-1ere\u002Fpf-archi-os\u002F4.linux-shell",{"title":377,"path":378,"stem":379},"Réseaux et protocoles","\u002Fnsi-1ere\u002Fpf-archi-os\u002Freseaux","1.nsi-1ere\u002Fpf-archi-os\u002F5.reseaux",{"title":381,"path":382,"stem":383,"children":384},"Langages et programmation","\u002Fnsi-1ere\u002Fpg-langages-prog","1.nsi-1ere\u002Fpg-langages-prog\u002F0.index",[385,386,390,394,398,402,406],{"title":381,"path":382,"stem":383},{"title":387,"path":388,"stem":389},"Diversité et unité des langages de programmation","\u002Fnsi-1ere\u002Fpg-langages-prog\u002Fdiversite-langages","1.nsi-1ere\u002Fpg-langages-prog\u002F1.diversite-langages",{"title":391,"path":392,"stem":393},"Constructions élémentaires","\u002Fnsi-1ere\u002Fpg-langages-prog\u002Fconstructions-elementaires","1.nsi-1ere\u002Fpg-langages-prog\u002F2.constructions-elementaires",{"title":395,"path":396,"stem":397},"Fonctions","\u002Fnsi-1ere\u002Fpg-langages-prog\u002Ffonctions","1.nsi-1ere\u002Fpg-langages-prog\u002F3.fonctions",{"title":399,"path":400,"stem":401},"Spécification d'une fonction","\u002Fnsi-1ere\u002Fpg-langages-prog\u002Fspecification","1.nsi-1ere\u002Fpg-langages-prog\u002F4.specification",{"title":403,"path":404,"stem":405},"Mise au point des programmes","\u002Fnsi-1ere\u002Fpg-langages-prog\u002Fmise-au-point","1.nsi-1ere\u002Fpg-langages-prog\u002F5.mise-au-point",{"title":407,"path":408,"stem":409},"Utilisation de bibliothèques","\u002Fnsi-1ere\u002Fpg-langages-prog\u002Fbibliotheques","1.nsi-1ere\u002Fpg-langages-prog\u002F6.bibliotheques",{"title":411,"path":412,"stem":413,"children":414},"Algorithmique","\u002Fnsi-1ere\u002Fph-algorithmique","1.nsi-1ere\u002Fph-algorithmique\u002F0.index",[415,416,420,424,428,432,436],{"title":411,"path":412,"stem":413},{"title":417,"path":418,"stem":419},"Parcours séquentiel d'un tableau","\u002Fnsi-1ere\u002Fph-algorithmique\u002Fparcours-sequentiel","1.nsi-1ere\u002Fph-algorithmique\u002F1.parcours-sequentiel",{"title":421,"path":422,"stem":423},"Bases de la complexité","\u002Fnsi-1ere\u002Fph-algorithmique\u002Fcomplexite-bases","1.nsi-1ere\u002Fph-algorithmique\u002F2.complexite-bases",{"title":425,"path":426,"stem":427},"Tris par sélection et par insertion","\u002Fnsi-1ere\u002Fph-algorithmique\u002Ftris","1.nsi-1ere\u002Fph-algorithmique\u002F3.tris",{"title":429,"path":430,"stem":431},"Recherche dichotomique","\u002Fnsi-1ere\u002Fph-algorithmique\u002Fdichotomie","1.nsi-1ere\u002Fph-algorithmique\u002F4.dichotomie",{"title":433,"path":434,"stem":435},"Algorithmes gloutons","\u002Fnsi-1ere\u002Fph-algorithmique\u002Fgloutons","1.nsi-1ere\u002Fph-algorithmique\u002F5.gloutons",{"title":437,"path":438,"stem":439},"Les k plus proches voisins (k-NN)","\u002Fnsi-1ere\u002Fph-algorithmique\u002Fknn","1.nsi-1ere\u002Fph-algorithmique\u002F6.knn",{"title":441,"path":442,"stem":443,"children":444},"NSI — Terminale","\u002Fnsi-tale","2.nsi-tale\u002F0.index",[445,446,450,476,498,536,560],{"title":441,"path":442,"stem":443},{"title":447,"path":448,"stem":449},"Review pédagogique — chapitres NSI Terminale (TA, TB, TC, TD, TE)","\u002Fnsi-tale\u002Freview","2.nsi-tale\u002FREVIEW",{"title":451,"path":452,"stem":453,"children":454},"Structures de données","\u002Fnsi-tale\u002Fta-structures-donnees","2.nsi-tale\u002Fta-structures-donnees\u002F0.index",[455,456,460,464,468,472],{"title":451,"path":452,"stem":453},{"title":457,"path":458,"stem":459},"Objet, classe, interface","\u002Fnsi-tale\u002Fta-structures-donnees\u002Finterface-implementation","2.nsi-tale\u002Fta-structures-donnees\u002F1.interface-implementation",{"title":461,"path":462,"stem":463},"Implémenter une structure — l'exemple de la file FIFO","\u002Fnsi-tale\u002Fta-structures-donnees\u002Fimplementer-une-structure","2.nsi-tale\u002Fta-structures-donnees\u002F2.implementer-une-structure",{"title":465,"path":466,"stem":467},"Listes, piles, files, dictionnaires","\u002Fnsi-tale\u002Fta-structures-donnees\u002Flistes-piles-files-dict","2.nsi-tale\u002Fta-structures-donnees\u002F3.listes-piles-files-dict",{"title":469,"path":470,"stem":471},"Arbres binaires","\u002Fnsi-tale\u002Fta-structures-donnees\u002Farbres-binaires","2.nsi-tale\u002Fta-structures-donnees\u002F4.arbres-binaires",{"title":473,"path":474,"stem":475},"Graphes","\u002Fnsi-tale\u002Fta-structures-donnees\u002Fgraphes","2.nsi-tale\u002Fta-structures-donnees\u002F5.graphes",{"title":477,"path":478,"stem":479,"children":480},"Bases de données","\u002Fnsi-tale\u002Ftb-bases-de-donnees","2.nsi-tale\u002Ftb-bases-de-donnees\u002F0.index",[481,482,486,490,494],{"title":477,"path":478,"stem":479},{"title":483,"path":484,"stem":485},"Le modèle relationnel","\u002Fnsi-tale\u002Ftb-bases-de-donnees\u002Fmodele-relationnel","2.nsi-tale\u002Ftb-bases-de-donnees\u002F1.modele-relationnel",{"title":487,"path":488,"stem":489},"Bases de données relationnelles et anomalies de schéma","\u002Fnsi-tale\u002Ftb-bases-de-donnees\u002Fbase-relationnelle","2.nsi-tale\u002Ftb-bases-de-donnees\u002F2.base-relationnelle",{"title":491,"path":492,"stem":493},"Le langage SQL","\u002Fnsi-tale\u002Ftb-bases-de-donnees\u002Fsql","2.nsi-tale\u002Ftb-bases-de-donnees\u002F3.sql",{"title":495,"path":496,"stem":497},"Les systèmes de gestion de bases de données","\u002Fnsi-tale\u002Ftb-bases-de-donnees\u002Fsgbd","2.nsi-tale\u002Ftb-bases-de-donnees\u002F4.sgbd",{"title":499,"path":500,"stem":501,"children":502},"Architectures matérielles, systèmes d'exploitation et réseaux","\u002Fnsi-tale\u002Ftc-archi-os-reseaux","2.nsi-tale\u002Ftc-archi-os-reseaux\u002F0.index",[503,504,508,512,516,520,524,528,532],{"title":499,"path":500,"stem":501},{"title":505,"path":506,"stem":507},"Le système sur puce (SoC)","\u002Fnsi-tale\u002Ftc-archi-os-reseaux\u002Fsysteme-sur-puce","2.nsi-tale\u002Ftc-archi-os-reseaux\u002F1.systeme-sur-puce",{"title":509,"path":510,"stem":511},"Processus et ordonnancement par l'OS","\u002Fnsi-tale\u002Ftc-archi-os-reseaux\u002Fprocessus-os","2.nsi-tale\u002Ftc-archi-os-reseaux\u002F2.processus-os",{"title":513,"path":514,"stem":515},"L'interblocage (deadlock)","\u002Fnsi-tale\u002Ftc-archi-os-reseaux\u002Finterblocage","2.nsi-tale\u002Ftc-archi-os-reseaux\u002F3.interblocage",{"title":517,"path":518,"stem":519},"Principes du routage","\u002Fnsi-tale\u002Ftc-archi-os-reseaux\u002Froutage-principes","2.nsi-tale\u002Ftc-archi-os-reseaux\u002F4.routage-principes",{"title":521,"path":522,"stem":523},"Protocoles de routage RIP et OSPF","\u002Fnsi-tale\u002Ftc-archi-os-reseaux\u002Fprotocoles-rip-ospf","2.nsi-tale\u002Ftc-archi-os-reseaux\u002F5.protocoles-rip-ospf",{"title":525,"path":526,"stem":527},"Chiffrement symétrique","\u002Fnsi-tale\u002Ftc-archi-os-reseaux\u002Fchiffrement-symetrique","2.nsi-tale\u002Ftc-archi-os-reseaux\u002F6.chiffrement-symetrique",{"title":529,"path":530,"stem":531},"Chiffrement asymétrique","\u002Fnsi-tale\u002Ftc-archi-os-reseaux\u002Fchiffrement-asymetrique","2.nsi-tale\u002Ftc-archi-os-reseaux\u002F7.chiffrement-asymetrique",{"title":533,"path":534,"stem":535},"HTTPS — l'échange de clé symétrique","\u002Fnsi-tale\u002Ftc-archi-os-reseaux\u002Fhttps-tls","2.nsi-tale\u002Ftc-archi-os-reseaux\u002F8.https-tls",{"title":381,"path":537,"stem":538,"children":539},"\u002Fnsi-tale\u002Ftd-langages-prog","2.nsi-tale\u002Ftd-langages-prog\u002F0.index",[540,541,544,548,552,556],{"title":381,"path":537,"stem":538},{"title":403,"path":542,"stem":543},"\u002Fnsi-tale\u002Ftd-langages-prog\u002Fmise-au-point","2.nsi-tale\u002Ftd-langages-prog\u002F1.mise-au-point",{"title":545,"path":546,"stem":547},"Modularité","\u002Fnsi-tale\u002Ftd-langages-prog\u002Fmodularite","2.nsi-tale\u002Ftd-langages-prog\u002F2.modularite",{"title":549,"path":550,"stem":551},"Récursivité","\u002Fnsi-tale\u002Ftd-langages-prog\u002Frecursivite","2.nsi-tale\u002Ftd-langages-prog\u002F3.recursivite",{"title":553,"path":554,"stem":555},"Paradigmes de programmation","\u002Fnsi-tale\u002Ftd-langages-prog\u002Fparadigmes","2.nsi-tale\u002Ftd-langages-prog\u002F4.paradigmes",{"title":557,"path":558,"stem":559},"Programme comme donnée — calculabilité et indécidabilité","\u002Fnsi-tale\u002Ftd-langages-prog\u002Fprogramme-comme-donnee","2.nsi-tale\u002Ftd-langages-prog\u002F5.programme-comme-donnee",{"title":411,"path":561,"stem":562,"children":563},"\u002Fnsi-tale\u002Fte-algorithmique","2.nsi-tale\u002Fte-algorithmique\u002F0.index",[564,565,569,573,577,581],{"title":411,"path":561,"stem":562},{"title":566,"path":567,"stem":568},"Algorithmes sur les arbres binaires","\u002Fnsi-tale\u002Fte-algorithmique\u002Farbres-binaires-algos","2.nsi-tale\u002Fte-algorithmique\u002F1.arbres-binaires-algos",{"title":570,"path":571,"stem":572},"Parcours de graphes — DFS, BFS, cycles, chemins","\u002Fnsi-tale\u002Fte-algorithmique\u002Fgraphes-parcours","2.nsi-tale\u002Fte-algorithmique\u002F2.graphes-parcours",{"title":574,"path":575,"stem":576},"Diviser pour régner","\u002Fnsi-tale\u002Fte-algorithmique\u002Fdiviser-pour-regner","2.nsi-tale\u002Fte-algorithmique\u002F3.diviser-pour-regner",{"title":578,"path":579,"stem":580},"Programmation dynamique","\u002Fnsi-tale\u002Fte-algorithmique\u002Fprogrammation-dynamique","2.nsi-tale\u002Fte-algorithmique\u002F4.programmation-dynamique",{"title":582,"path":583,"stem":584},"Recherche textuelle — l'algorithme de Boyer-Moore","\u002Fnsi-tale\u002Fte-algorithmique\u002Frecherche-textuelle","2.nsi-tale\u002Fte-algorithmique\u002F5.recherche-textuelle",[586,1207,1508,2090],{"id":587,"title":169,"bo":588,"body":590,"description":1190,"eval":1191,"extension":1192,"labo":1191,"meta":1193,"navigation":1194,"path":170,"quizzes":1195,"readingTime":1204,"seo":1205,"stem":171,"tp":1191,"__hash__":1206},"cours\u002F0.snt-2nde\u002Fsg-photo-numerique\u002F1.pixels-resolution.md",[589],"SG02",{"type":591,"value":592,"toc":1180},"minimark",[593,598,621,624,628,638,648,658,710,717,748,752,771,797,813,817,824,850,873,877,892,1031,1053,1120,1142,1146,1169,1173],[594,595,597],"h2",{"id":596},"introduction","Introduction",[599,600,601,602,606,607,610,611,610,614,610,617,620],"p",{},"Quand on parle d'un appareil photo « de 24 mégapixels », à quoi ce nombre\ncorrespond-il exactement ? Il désigne le nombre de cellules sensibles à la\nlumière sur le ",[603,604,605],"strong",{},"capteur"," — un petit composant électronique de quelques\ncentimètres carrés, niché derrière l'objectif. Mais ce nombre ne dit pas\ntout : un même appareil produit des images de tailles très différentes\nselon les réglages. Ce premier cours pose les briques de vocabulaire\nindispensables : ",[603,608,609],{},"photosite",", ",[603,612,613],{},"pixel",[603,615,616],{},"résolution",[603,618,619],{},"profondeur de\ncouleur",".",[622,623],"bo-ref",{"code":589},[594,625,627],{"id":626},"le-capteur-et-ses-photosites","Le capteur et ses photosites",[599,629,630,631,633,634,637],{},"Le ",[603,632,605],{}," d'un appareil photo numérique est une grille de minuscules\ncellules sensibles à la lumière, appelées ",[603,635,636],{},"photosites",". Chaque photosite\nmesure la quantité de lumière qu'il reçoit pendant le temps d'exposition.",[639,640,641],"note",{},[599,642,643,644,647],{},"Un photosite ne mesure ",[603,645,646],{},"qu'une seule"," valeur — une intensité lumineuse. Pour\nobtenir une information de couleur, on place devant chaque photosite un petit\nfiltre : rouge, vert ou bleu. Un photosite « rouge » ne mesure donc que la\nquantité de lumière rouge qui lui parvient.",[599,649,630,650,653,654,657],{},[603,651,652],{},"nombre de photosites"," sur un capteur définit sa ",[603,655,656],{},"résolution capteur",".\nUn capteur de 24 millions de photosites est dit « 24 Mpx » (mégapixels). À\ntitre d'ordre de grandeur :",[659,660,661,674],"table",{},[662,663,664],"thead",{},[665,666,667,671],"tr",{},[668,669,670],"th",{},"Appareil",[668,672,673],{},"Résolution capteur typique",[675,676,677,686,694,702],"tbody",{},[665,678,679,683],{},[680,681,682],"td",{},"Smartphone d'entrée de gamme",[680,684,685],{},"8 à 12 Mpx",[665,687,688,691],{},[680,689,690],{},"Smartphone haut de gamme",[680,692,693],{},"50 à 200 Mpx",[665,695,696,699],{},[680,697,698],{},"Appareil reflex amateur",[680,700,701],{},"20 à 30 Mpx",[665,703,704,707],{},[680,705,706],{},"Appareil professionnel",[680,708,709],{},"45 à 100 Mpx",[711,712],"illustration",{"alt":713,"kind":714,"src":715,"svg":716},"Schéma d'un capteur avec ses photosites","schema","\u002Fillustrations\u002F0.snt-2nde\u002Fsg-photo-numerique\u002Fcapteur-bayer.svg","\u003Csvg class=\"illustration-svg\" xmlns=\"http:\u002F\u002Fwww.w3.org\u002F2000\u002Fsvg\" viewBox=\"0 0 480 300\" role=\"img\" aria-label=\"Vue très rapprochée d'un capteur photo : une grille régulière de photosites avec filtres colorés en mosaïque, motif de Bayer RGGB (rouge, vert, vert, bleu), avec la légende un photosite égale une case\">\n  \u003Ctitle>Capteur photo — mosaïque de Bayer (motif RGGB)\u003C\u002Ftitle>\n  \u003Cstyle>\n    \u002F* Exception assumée au monochrome : les rouge\u002Fvert\u002Fbleu PORTENT le sens\n       pédagogique du motif RGGB (cf. brief). Le reste (cadre, traits, texte,\n       légende) reste en tokens DS. *\u002F\n    .cb-frame   { fill: none; stroke: var(--diagram-node-border); stroke-width: 2; }\n    .cb-grid    { stroke: var(--diagram-surface); stroke-width: 2; }\n    .cb-red     { fill: #d24b4b; }\n    .cb-green   { fill: #4caf6a; }\n    .cb-blue    { fill: #4b78d2; }\n    .cb-leader  { stroke: var(--diagram-line); stroke-width: 1.5; fill: none; }\n    .cb-callout { fill: var(--diagram-node-bg); stroke: var(--diagram-node-border); stroke-width: 1.5; }\n    .cb-label   { fill: var(--diagram-text); font-family: Geist, Inter, system-ui, sans-serif; font-size: 13px; font-weight: 500; }\n    .cb-legend  { fill: var(--diagram-line); font-family: 'JetBrains Mono', monospace; font-size: 11px; letter-spacing: 0.5px; }\n    .cb-eyebrow { fill: var(--diagram-line); font-family: 'JetBrains Mono', monospace; font-size: 10px; letter-spacing: 1.5px; }\n  \u003C\u002Fstyle>\n\n  \u003Ctext x=\"40\" y=\"28\" class=\"cb-eyebrow\">VUE RAPPROCHÉE DU CAPTEUR\u003C\u002Ftext>\n\n  \u003C!-- grille 6×6 de photosites, motif Bayer RGGB par bloc 2×2 :\n       ligne paire   = V B V B …   ligne impaire = R V R V …  -->\n  \u003Cg>\n    \u003C!-- ligne 0 : R V R V R V -->\n    \u003Crect x=\"40\"  y=\"44\" width=\"40\" height=\"40\" class=\"cb-red\"\u002F>\n    \u003Crect x=\"80\"  y=\"44\" width=\"40\" height=\"40\" class=\"cb-green\"\u002F>\n    \u003Crect x=\"120\" y=\"44\" width=\"40\" height=\"40\" class=\"cb-red\"\u002F>\n    \u003Crect x=\"160\" y=\"44\" width=\"40\" height=\"40\" class=\"cb-green\"\u002F>\n    \u003Crect x=\"200\" y=\"44\" width=\"40\" height=\"40\" class=\"cb-red\"\u002F>\n    \u003Crect x=\"240\" y=\"44\" width=\"40\" height=\"40\" class=\"cb-green\"\u002F>\n    \u003C!-- ligne 1 : V B V B V B -->\n    \u003Crect x=\"40\"  y=\"84\" width=\"40\" height=\"40\" class=\"cb-green\"\u002F>\n    \u003Crect x=\"80\"  y=\"84\" width=\"40\" height=\"40\" class=\"cb-blue\"\u002F>\n    \u003Crect x=\"120\" y=\"84\" width=\"40\" height=\"40\" class=\"cb-green\"\u002F>\n    \u003Crect x=\"160\" y=\"84\" width=\"40\" height=\"40\" class=\"cb-blue\"\u002F>\n    \u003Crect x=\"200\" y=\"84\" width=\"40\" height=\"40\" class=\"cb-green\"\u002F>\n    \u003Crect x=\"240\" y=\"84\" width=\"40\" height=\"40\" class=\"cb-blue\"\u002F>\n    \u003C!-- ligne 2 : R V R V R V -->\n    \u003Crect x=\"40\"  y=\"124\" width=\"40\" height=\"40\" class=\"cb-red\"\u002F>\n    \u003Crect x=\"80\"  y=\"124\" width=\"40\" height=\"40\" class=\"cb-green\"\u002F>\n    \u003Crect x=\"120\" y=\"124\" width=\"40\" height=\"40\" class=\"cb-red\"\u002F>\n    \u003Crect x=\"160\" y=\"124\" width=\"40\" height=\"40\" class=\"cb-green\"\u002F>\n    \u003Crect x=\"200\" y=\"124\" width=\"40\" height=\"40\" class=\"cb-red\"\u002F>\n    \u003Crect x=\"240\" y=\"124\" width=\"40\" height=\"40\" class=\"cb-green\"\u002F>\n    \u003C!-- ligne 3 : V B V B V B -->\n    \u003Crect x=\"40\"  y=\"164\" width=\"40\" height=\"40\" class=\"cb-green\"\u002F>\n    \u003Crect x=\"80\"  y=\"164\" width=\"40\" height=\"40\" class=\"cb-blue\"\u002F>\n    \u003Crect x=\"120\" y=\"164\" width=\"40\" height=\"40\" class=\"cb-green\"\u002F>\n    \u003Crect x=\"160\" y=\"164\" width=\"40\" height=\"40\" class=\"cb-blue\"\u002F>\n    \u003Crect x=\"200\" y=\"164\" width=\"40\" height=\"40\" class=\"cb-green\"\u002F>\n    \u003Crect x=\"240\" y=\"164\" width=\"40\" height=\"40\" class=\"cb-blue\"\u002F>\n    \u003C!-- ligne 4 : R V R V R V -->\n    \u003Crect x=\"40\"  y=\"204\" width=\"40\" height=\"40\" class=\"cb-red\"\u002F>\n    \u003Crect x=\"80\"  y=\"204\" width=\"40\" height=\"40\" class=\"cb-green\"\u002F>\n    \u003Crect x=\"120\" y=\"204\" width=\"40\" height=\"40\" class=\"cb-red\"\u002F>\n    \u003Crect x=\"160\" y=\"204\" width=\"40\" height=\"40\" class=\"cb-green\"\u002F>\n    \u003Crect x=\"200\" y=\"204\" width=\"40\" height=\"40\" class=\"cb-red\"\u002F>\n    \u003Crect x=\"240\" y=\"204\" width=\"40\" height=\"40\" class=\"cb-green\"\u002F>\n    \u003C!-- ligne 5 : V B V B V B -->\n    \u003Crect x=\"40\"  y=\"244\" width=\"40\" height=\"40\" class=\"cb-green\"\u002F>\n    \u003Crect x=\"80\"  y=\"244\" width=\"40\" height=\"40\" class=\"cb-blue\"\u002F>\n    \u003Crect x=\"120\" y=\"244\" width=\"40\" height=\"40\" class=\"cb-green\"\u002F>\n    \u003Crect x=\"160\" y=\"244\" width=\"40\" height=\"40\" class=\"cb-blue\"\u002F>\n    \u003Crect x=\"200\" y=\"244\" width=\"40\" height=\"40\" class=\"cb-green\"\u002F>\n    \u003Crect x=\"240\" y=\"244\" width=\"40\" height=\"40\" class=\"cb-blue\"\u002F>\n  \u003C\u002Fg>\n\n  \u003C!-- lignes de grille (séparateurs entre cases) -->\n  \u003Cg class=\"cb-grid\">\n    \u003Cline x1=\"80\"  y1=\"44\" x2=\"80\"  y2=\"284\"\u002F>\n    \u003Cline x1=\"120\" y1=\"44\" x2=\"120\" y2=\"284\"\u002F>\n    \u003Cline x1=\"160\" y1=\"44\" x2=\"160\" y2=\"284\"\u002F>\n    \u003Cline x1=\"200\" y1=\"44\" x2=\"200\" y2=\"284\"\u002F>\n    \u003Cline x1=\"240\" y1=\"44\" x2=\"240\" y2=\"284\"\u002F>\n    \u003Cline x1=\"40\" y1=\"84\"  x2=\"280\" y2=\"84\"\u002F>\n    \u003Cline x1=\"40\" y1=\"124\" x2=\"280\" y2=\"124\"\u002F>\n    \u003Cline x1=\"40\" y1=\"164\" x2=\"280\" y2=\"164\"\u002F>\n    \u003Cline x1=\"40\" y1=\"204\" x2=\"280\" y2=\"204\"\u002F>\n    \u003Cline x1=\"40\" y1=\"244\" x2=\"280\" y2=\"244\"\u002F>\n  \u003C\u002Fg>\n\n  \u003C!-- cadre du capteur (accent indigo) -->\n  \u003Crect x=\"40\" y=\"44\" width=\"240\" height=\"240\" rx=\"3\" class=\"cb-frame\" fill=\"none\"\u002F>\n\n  \u003C!-- callout : un photosite = une case -->\n  \u003Crect x=\"220\" y=\"84\" width=\"40\" height=\"40\" rx=\"2\" fill=\"none\" stroke=\"var(--diagram-text)\" stroke-width=\"2.5\"\u002F>\n  \u003Cpath class=\"cb-leader\" d=\"M 260 104 L 320 104\"\u002F>\n  \u003Crect x=\"320\" y=\"120\" width=\"132\" height=\"56\" rx=\"6\" class=\"cb-callout\"\u002F>\n  \u003Ctext x=\"386\" y=\"143\" text-anchor=\"middle\" class=\"cb-label\">un photosite\u003C\u002Ftext>\n  \u003Ctext x=\"386\" y=\"163\" text-anchor=\"middle\" class=\"cb-legend\">= une case\u003C\u002Ftext>\n\n  \u003C!-- légende des couleurs RGGB -->\n  \u003Cg>\n    \u003Crect x=\"320\" y=\"206\" width=\"14\" height=\"14\" class=\"cb-red\"\u002F>\n    \u003Ctext x=\"340\" y=\"217\" class=\"cb-legend\">filtre rouge\u003C\u002Ftext>\n    \u003Crect x=\"320\" y=\"226\" width=\"14\" height=\"14\" class=\"cb-green\"\u002F>\n    \u003Ctext x=\"340\" y=\"237\" class=\"cb-legend\">filtre vert (×2)\u003C\u002Ftext>\n    \u003Crect x=\"320\" y=\"246\" width=\"14\" height=\"14\" class=\"cb-blue\"\u002F>\n    \u003Ctext x=\"340\" y=\"257\" class=\"cb-legend\">filtre bleu\u003C\u002Ftext>\n  \u003C\u002Fg>\n\u003C\u002Fsvg>\n",[718,719,723,730],"self-eval-qcm",{"correct":720,"explanation":721,"slug":722},"3","Mpx signifie millions de pixels (ou de photosites). 12 Mpx = 12 millions.","pixels-resolution-c1",[724,725,727],"template",{"v-slot:question":726},"",[599,728,729],{},"Un capteur '12 Mpx' contient environ combien de photosites ?",[724,731,732],{"v-slot:choices":726},[733,734,735,739,742,745],"ul",{},[736,737,738],"li",{},"12 000",[736,740,741],{},"120 000",[736,743,744],{},"1 200 000",[736,746,747],{},"12 000 000",[594,749,751],{"id":750},"le-pixel-de-limage","Le pixel de l'image",[599,753,754,755,758,759,762,763,766,767,770],{},"Une fois la photo prise, l'appareil produit un ",[603,756,757],{},"fichier image"," composé de\n",[603,760,761],{},"pixels",". Un pixel est un point coloré, défini par ",[603,764,765],{},"trois valeurs"," : son\nintensité de rouge, de vert et de bleu (le fameux ",[603,768,769],{},"mode RGB",").",[772,773,774,777],"tip",{},[599,775,776],{},"Retenez la distinction :",[733,778,779,788],{},[736,780,781,782,784,785,787],{},"Un ",[603,783,609],{}," est une cellule physique du ",[603,786,605],{}," (matériel).",[736,789,781,790,792,793,796],{},[603,791,613],{}," est un point coloré de l'",[603,794,795],{},"image"," finale (fichier informatique).",[599,798,799,800,803,804,808,809,812],{},"La ",[603,801,802],{},"résolution de l'image"," est le nombre de pixels qui la composent :\nlargeur × hauteur. Une image de ",[805,806,807],"code",{},"4000 × 3000"," pixels contient donc\n",[805,810,811],{},"4000 × 3000 = 12 000 000"," pixels, soit 12 Mpx.",[594,814,816],{"id":815},"capteur-image-pourquoi-les-résolutions-diffèrent","Capteur ≠ image : pourquoi les résolutions diffèrent",[599,818,819,820,823],{},"Une question naturelle : si un capteur a 24 millions de photosites, l'image\nfait-elle 24 millions de pixels ? ",[603,821,822],{},"Pas toujours."," Voici trois raisons.",[825,826,827,833,839],"ol",{},[736,828,829,832],{},[603,830,831],{},"Les réglages de l'appareil",". La plupart des appareils permettent de\nchoisir une résolution d'image plus petite que celle du capteur (par\nexemple pour économiser de l'espace de stockage).",[736,834,835,838],{},[603,836,837],{},"Le format de sortie",". Un capteur 4:3 peut produire une image 16:9 en\n« rognant » sur les bords — le nombre de pixels diminue.",[736,840,841,844,845,849],{},[603,842,843],{},"Le post-traitement",". Certains appareils combinent les mesures de\nplusieurs photosites voisins pour calculer un seul pixel (technique appelée\n",[846,847,848],"em",{},"pixel binning","), surtout sur les smartphones.",[718,851,855,860],{"correct":852,"explanation":853,"slug":854},"1","L'image finale dépend des réglages et du traitement : on peut produire des images plus petites que ce que le capteur peut au maximum.","pixels-resolution-c2",[724,856,857],{"v-slot:question":726},[599,858,859],{},"Un capteur de 48 Mpx peut-il produire une image de 12 Mpx ?",[724,861,862],{"v-slot:choices":726},[733,863,864,867,870],{},[736,865,866],{},"Non, jamais",[736,868,869],{},"Oui, en choisissant une résolution réduite ou par pixel binning",[736,871,872],{},"Oui, mais seulement la nuit",[594,874,876],{"id":875},"la-profondeur-de-couleur","La profondeur de couleur",[599,878,879,880,883,884,887,888,891],{},"Reste à savoir avec ",[603,881,882],{},"quelle précision"," chaque pixel est codé. La\n",[603,885,886],{},"profondeur de couleur"," désigne le nombre de ",[603,889,890],{},"bits"," utilisés pour coder\nl'intensité d'une composante (rouge, vert ou bleu) d'un pixel.",[639,893,894,897],{},[599,895,896],{},"Le calcul du nombre de niveaux représentables est simple :",[898,899,902],"span",{"className":900},[901],"katex-display",[898,903,906,944],{"className":904},[905],"katex",[898,907,910],{"className":908},[909],"katex-mathml",[911,912,915],"math",{"xmlns":913,"display":914},"http:\u002F\u002Fwww.w3.org\u002F1998\u002FMath\u002FMathML","block",[916,917,918,939],"semantics",{},[919,920,921,925,929],"mrow",{},[922,923,924],"mtext",{},"nombre de niveaux",[926,927,928],"mo",{},"=",[930,931,932,936],"msup",{},[933,934,935],"mn",{},"2",[922,937,938],{},"profondeur",[940,941,943],"annotation",{"encoding":942},"application\u002Fx-tex","\\text{nombre de niveaux} = 2^{\\text{profondeur}}",[898,945,949,978],{"className":946,"ariaHidden":948},[947],"katex-html","true",[898,950,953,958,966,971,975],{"className":951},[952],"base",[898,954],{"className":955,"style":957},[956],"strut","height:0.6944em;",[898,959,963],{"className":960},[961,962],"mord","text",[898,964,924],{"className":965},[961],[898,967],{"className":968,"style":970},[969],"mspace","margin-right:0.2778em;",[898,972,928],{"className":973},[974],"mrel",[898,976],{"className":977,"style":970},[969],[898,979,981,985],{"className":980},[952],[898,982],{"className":983,"style":984},[956],"height:0.8991em;",[898,986,988,991],{"className":987},[961],[898,989,935],{"className":990},[961],[898,992,995],{"className":993},[994],"msupsub",[898,996,999],{"className":997},[998],"vlist-t",[898,1000,1003],{"className":1001},[1002],"vlist-r",[898,1004,1007],{"className":1005,"style":984},[1006],"vlist",[898,1008,1010,1015],{"style":1009},"top:-3.113em;margin-right:0.05em;",[898,1011],{"className":1012,"style":1014},[1013],"pstrut","height:2.7em;",[898,1016,1022],{"className":1017},[1018,1019,1020,1021],"sizing","reset-size6","size3","mtight",[898,1023,1025],{"className":1024},[961,1021],[898,1026,1028],{"className":1027},[961,962,1021],[898,1029,938],{"className":1030},[961,1021],[599,1032,1033,1034,1037,1038,1041,1042,1045,1046,1049,1050,770],{},"Cas le plus courant : ",[603,1035,1036],{},"8 bits par composante",", soit ",[805,1039,1040],{},"2^8 = 256"," niveaux de\nrouge, 256 niveaux de vert, 256 niveaux de bleu. Cela donne au total\n",[805,1043,1044],{},"256 × 256 × 256 = 16 777 216"," couleurs possibles par pixel. On parle alors\nd'image ",[603,1047,1048],{},"24 bits"," au total (",[805,1051,1052],{},"8 × 3",[659,1054,1055,1068],{},[662,1056,1057],{},[665,1058,1059,1062,1065],{},[668,1060,1061],{},"Profondeur (par composante)",[668,1063,1064],{},"Niveaux par composante",[668,1066,1067],{},"Couleurs totales",[675,1069,1070,1080,1091,1109],{},[665,1071,1072,1075,1077],{},[680,1073,1074],{},"1 bit",[680,1076,935],{},[680,1078,1079],{},"8",[665,1081,1082,1085,1088],{},[680,1083,1084],{},"4 bits",[680,1086,1087],{},"16",[680,1089,1090],{},"4 096",[665,1092,1093,1099,1104],{},[680,1094,1095,1098],{},[603,1096,1097],{},"8 bits"," (standard)",[680,1100,1101],{},[603,1102,1103],{},"256",[680,1105,1106],{},[603,1107,1108],{},"≈ 16,7 millions",[665,1110,1111,1114,1117],{},[680,1112,1113],{},"10 bits (HDR)",[680,1115,1116],{},"1 024",[680,1118,1119],{},"≈ 1 milliard",[718,1121,1124,1129],{"correct":935,"explanation":1122,"slug":1123},"2^4 = 16. Avec 4 bits, on dispose de 16 valeurs possibles, de 0 à 15.","pixels-resolution-c3",[724,1125,1126],{"v-slot:question":726},[599,1127,1128],{},"Combien de niveaux peut-on coder avec une profondeur de 4 bits ?",[724,1130,1131],{"v-slot:choices":726},[733,1132,1133,1136,1138,1140],{},[736,1134,1135],{},"4",[736,1137,1079],{},[736,1139,1087],{},[736,1141,1103],{},[594,1143,1145],{"id":1144},"pièges-courants","Pièges courants",[1147,1148,1149],"warning",{},[733,1150,1151,1157,1163],{},[736,1152,1153,1156],{},[603,1154,1155],{},"Plus de mégapixels ≠ meilleure photo."," Un capteur très dense entasse des\nphotosites minuscules qui captent peu de lumière — la photo de nuit peut être\nmeilleure avec un capteur de 12 Mpx « généreux » qu'avec un 200 Mpx étriqué.",[736,1158,1159,1162],{},[603,1160,1161],{},"Photosite et pixel ne sont pas synonymes."," Le premier est sur le capteur,\nle second est dans l'image. La confusion est fréquente mais fausse.",[736,1164,1165,1168],{},[603,1166,1167],{},"La résolution ne dit rien de la couleur."," Une image 12 Mpx en 24 bits et\nune image 12 Mpx en 1 bit ont le même nombre de pixels mais ne pèsent pas du\ntout le même poids.",[594,1170,1172],{"id":1171},"pour-aller-plus-loin","Pour aller plus loin",[599,1174,1175,1176,1179],{},"Si vous photographiez en ",[846,1177,1178],{},"RAW"," (le format brut du capteur, sans traitement),\nvous récupérez les mesures directes de chaque photosite. C'est plus lourd à\nstocker, mais beaucoup plus riche à retoucher — chaque composante est codée\nsur 12 ou 14 bits au lieu de 8. Le métier de retoucheur photo s'appuie\nlargement sur ce surplus d'information.",{"title":726,"searchDepth":1181,"depth":1181,"links":1182},2,[1183,1184,1185,1186,1187,1188,1189],{"id":596,"depth":1181,"text":597},{"id":626,"depth":1181,"text":627},{"id":750,"depth":1181,"text":751},{"id":815,"depth":1181,"text":816},{"id":875,"depth":1181,"text":876},{"id":1144,"depth":1181,"text":1145},{"id":1171,"depth":1181,"text":1172},"Comprendre la différence entre les cellules du capteur, les points de l'image, et la profondeur de couleur.",null,"md",{},true,[1196,1200,1202],{"slug":722,"kind":1197,"question":729,"choices":1198,"correct":720,"multi":1199,"explanation":721},"qcm",[738,741,744,747],false,{"slug":854,"kind":1197,"question":859,"choices":1201,"correct":852,"multi":1199,"explanation":853},[866,869,872],{"slug":1123,"kind":1197,"question":1128,"choices":1203,"correct":935,"multi":1199,"explanation":1122},[1135,1079,1087,1103],1,{"title":169,"description":1190},"bP5asbjsdTt2xNT3VdSq_MANvS5J-xHJ4YHHnWS-NB4",{"id":1208,"title":173,"bo":1209,"body":1211,"description":1497,"eval":1191,"extension":1192,"labo":1191,"meta":1498,"navigation":1194,"path":174,"quizzes":1499,"readingTime":1204,"seo":1506,"stem":175,"tp":1191,"__hash__":1507},"cours\u002F0.snt-2nde\u002Fsg-photo-numerique\u002F2.algorithmes-photo.md",[1210],"SG03",{"type":591,"value":1212,"toc":1487},[1213,1215,1229,1232,1234,1238,1245,1267,1274,1296,1300,1303,1317,1326,1330,1336,1358,1364,1368,1379,1388,1392,1411,1416,1420,1444,1466,1468],[594,1214,597],{"id":596},[599,1216,1217,1218,1221,1222,1225,1226,620],{},"Quand vous appuyez sur le déclencheur, vous croyez « capturer la réalité ».\nEn vérité, votre appareil — qu'il s'agisse d'un smartphone ou d'un reflex —\nexécute en quelques fractions de seconde ",[603,1219,1220],{},"plusieurs algorithmes",", chacun\nprenant des décisions sur la mise au point, la lumière, les couleurs, le\nbruit. Ce qui sort du capteur est une ",[603,1223,1224],{},"soupe de mesures brutes"," ; ce qui\narrive dans le fichier final est une ",[603,1227,1228],{},"image calculée",[599,1230,1231],{},"Ce cours présente les algorithmes les plus emblématiques qui transforment les\nmesures du capteur en une photo nette, contrastée, équilibrée.",[622,1233],{"code":1210},[594,1235,1237],{"id":1236},"lautofocus-où-faire-la-mise-au-point","L'autofocus — où faire la mise au point ?",[599,1239,1240,1241,1244],{},"L'",[603,1242,1243],{},"autofocus"," (mise au point automatique) cherche à rendre nette une zone\nprécise de la scène. Plusieurs stratégies sont possibles.",[639,1246,1247],{},[733,1248,1249,1255,1261],{},[736,1250,1251,1254],{},[603,1252,1253],{},"Autofocus par contraste"," : l'appareil déplace l'objectif pas à pas et\nmesure la netteté (les contours nets ont un fort contraste local).",[736,1256,1257,1260],{},[603,1258,1259],{},"Autofocus par détection de phase"," : des photosites spécialisés mesurent\nun décalage qui indique directement la distance.",[736,1262,1263,1266],{},[603,1264,1265],{},"Autofocus par intelligence artificielle"," : un modèle reconnaît un visage,\nun œil ou un animal, et y place la mise au point.",[599,1268,1269,1270,1273],{},"Dans tous les cas, l'appareil exécute un algorithme ",[603,1271,1272],{},"avant même"," que la photo\nne soit prise — pour décider où regarder.",[718,1275,1278,1283],{"correct":852,"explanation":1276,"slug":1277},"L'autofocus par contraste a besoin de variations nettes (contours) pour mesurer la netteté. Un mur uniforme n'en offre pas.","algorithmes-photo-c1",[724,1279,1280],{"v-slot:question":726},[599,1281,1282],{},"Pourquoi l'autofocus peut-il échouer sur un mur uni ?",[724,1284,1285],{"v-slot:choices":726},[733,1286,1287,1290,1293],{},[736,1288,1289],{},"Parce que le mur est trop blanc",[736,1291,1292],{},"Parce qu’il manque de contraste local à mesurer",[736,1294,1295],{},"Parce que le capteur est sale",[594,1297,1299],{"id":1298},"la-balance-des-blancs-quelle-couleur-est-neutre","La balance des blancs — quelle couleur est neutre ?",[599,1301,1302],{},"Selon la source lumineuse (soleil, néon, ampoule, écran), le blanc « réel »\nn'a pas la même couleur sur le capteur. Une feuille blanche photographiée sous\nune ampoule jaune sera mesurée… jaune.",[599,1304,799,1305,1308,1309,1312,1313,1316],{},[603,1306,1307],{},"balance des blancs"," est l'algorithme qui ",[603,1310,1311],{},"corrige"," ces dérives : il\nidentifie ce qui devrait être blanc dans la scène et ",[603,1314,1315],{},"réajuste les\ncomposantes R, G, B"," de tous les pixels en conséquence.",[772,1318,1319],{},[599,1320,1321,1322,1325],{},"On peut souvent ",[603,1323,1324],{},"désactiver"," la balance des blancs automatique et choisir un\nréglage manuel (« lumière du jour », « tungstène », « fluorescent »…). Utile en\nphoto d'art ou pour conserver une ambiance.",[594,1327,1329],{"id":1328},"lexposition-et-le-hdr","L'exposition et le HDR",[599,1331,1240,1332,1335],{},[603,1333,1334],{},"exposition"," mesure la quantité de lumière qui atteint le capteur. Trop\nexposée, l'image est blanche (« cramée ») ; sous-exposée, elle est sombre. Un\nalgorithme choisit en temps réel la vitesse d'obturation et l'ouverture pour\nviser une exposition correcte.",[599,1337,630,1338,1341,1342,1345,1346,1349,1350,1353,1354,1357],{},[603,1339,1340],{},"HDR"," (",[846,1343,1344],{},"High Dynamic Range",") va plus loin : l'appareil prend ",[603,1347,1348],{},"plusieurs\nphotos"," très rapprochées avec des expositions différentes, puis ",[603,1351,1352],{},"fusionne","\nles zones les mieux exposées de chaque cliché. Une seule pression du\ndéclencheur, mais ",[603,1355,1356],{},"trois ou cinq photos"," en arrière-plan.",[711,1359],{"alt":1360,"kind":1361,"src":1362,"svg":1363},"Trois prises de vue (sous-exposée, normale, sur-exposée) fusionnées en une seule image HDR","mermaid","\u002Fillustrations\u002F0.snt-2nde\u002Fsg-photo-numerique\u002Fhdr-fusion.svg","\u003Csvg id=\"ill-0-snt-2nde-sg-photo-numerique-hdr-fusion\" xmlns=\"http:\u002F\u002Fwww.w3.org\u002F2000\u002Fsvg\" xmlns:xlink=\"http:\u002F\u002Fwww.w3.org\u002F1999\u002Fxlink\" class=\"illustration-svg flowchart\" viewBox=\"0 0 538.40625 178\" role=\"graphics-document document\" aria-roledescription=\"flowchart-v2\">\u003Cstyle>#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion{font-family:Geist,Inter,system-ui,-apple-system,sans-serif;font-size:14px;fill:var(--diagram-text);}@keyframes edge-animation-frame{from{stroke-dashoffset:0;}}@keyframes dash{to{stroke-dashoffset:0;}}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .edge-animation-slow{stroke-dasharray:9,5!important;stroke-dashoffset:900;animation:dash 50s linear infinite;stroke-linecap:round;}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .edge-animation-fast{stroke-dasharray:9,5!important;stroke-dashoffset:900;animation:dash 20s linear infinite;stroke-linecap:round;}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .error-icon{fill:#fdecec;}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .error-text{fill:var(--diagram-text);stroke:var(--diagram-text);}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .edge-thickness-normal{stroke-width:1px;}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .edge-thickness-thick{stroke-width:3.5px;}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .edge-pattern-solid{stroke-dasharray:0;}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .edge-thickness-invisible{stroke-width:0;fill:none;}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .edge-pattern-dashed{stroke-dasharray:3;}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .edge-pattern-dotted{stroke-dasharray:2;}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .marker{fill:var(--diagram-line);stroke:var(--diagram-line);}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .marker.cross{stroke:var(--diagram-line);}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion svg{font-family:Geist,Inter,system-ui,-apple-system,sans-serif;font-size:14px;}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion p{margin:0;}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .label{font-family:Geist,Inter,system-ui,-apple-system,sans-serif;color:var(--diagram-text);}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .cluster-label text{fill:var(--diagram-line);}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .cluster-label span{color:var(--diagram-line);}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .cluster-label span p{background-color:transparent;}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .label text,#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion span{fill:var(--diagram-text);color:var(--diagram-text);}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .node rect,#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .node circle,#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .node ellipse,#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .node polygon,#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .node path{fill:var(--diagram-node-bg);stroke:var(--diagram-node-border);stroke-width:1px;}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .rough-node .label text,#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .node .label text,#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .image-shape .label,#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .icon-shape .label{text-anchor:middle;}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .node .katex path{fill:#000;stroke:#000;stroke-width:1px;}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .rough-node .label,#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .node .label,#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .image-shape .label,#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .icon-shape .label{text-align:center;}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .node.clickable{cursor:pointer;}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .root .anchor path{fill:var(--diagram-line)!important;stroke-width:0;stroke:var(--diagram-line);}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .arrowheadPath{fill:rgba(255, 255, 255, 0);}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .edgePath .path{stroke:var(--diagram-line);stroke-width:1px;}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .flowchart-link{stroke:var(--diagram-line);fill:none;}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .edgeLabel{background-color:var(--diagram-surface);text-align:center;}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .edgeLabel p{background-color:var(--diagram-surface);}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .edgeLabel rect{opacity:0.5;background-color:var(--diagram-surface);fill:var(--diagram-surface);}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .labelBkg{background-color:rgba(250, 251, 252, 0.5);}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .cluster rect{fill:var(--diagram-surface);stroke:var(--diagram-border);stroke-width:1px;}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .cluster text{fill:var(--diagram-line);}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .cluster span{color:var(--diagram-line);}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion div.mermaidTooltip{position:absolute;text-align:center;max-width:200px;padding:2px;font-family:Geist,Inter,system-ui,-apple-system,sans-serif;font-size:12px;background:var(--diagram-surface);border:1px solid var(--diagram-border);border-radius:2px;pointer-events:none;z-index:100;}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .flowchartTitleText{text-anchor:middle;font-size:18px;fill:var(--diagram-text);}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion rect.text{fill:none;stroke-width:0;}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .icon-shape,#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .image-shape{background-color:var(--diagram-surface);text-align:center;}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .icon-shape p,#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .image-shape p{background-color:var(--diagram-surface);padding:2px;}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .icon-shape .label rect,#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .image-shape .label rect{opacity:0.5;background-color:var(--diagram-surface);fill:var(--diagram-surface);}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .label-icon{display:inline-block;height:1em;overflow:visible;vertical-align:-0.125em;}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .node .label-icon path{fill:currentColor;stroke:revert;stroke-width:revert;}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .node .neo-node{stroke:var(--diagram-node-border);}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [data-look=\"neo\"].node rect,#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [data-look=\"neo\"].cluster rect,#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [data-look=\"neo\"].node polygon{stroke:url(#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion-gradient);filter:drop-shadow( 1px 2px 2px rgba(185,185,185,1));}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [data-look=\"neo\"].node path{stroke:url(#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion-gradient);stroke-width:1px;}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [data-look=\"neo\"].node .outer-path{filter:drop-shadow( 1px 2px 2px rgba(185,185,185,1));}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [data-look=\"neo\"].node .neo-line path{stroke:var(--diagram-node-border);filter:none;}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [data-look=\"neo\"].node circle{stroke:url(#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion-gradient);filter:drop-shadow( 1px 2px 2px rgba(185,185,185,1));}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [data-look=\"neo\"].node circle .state-start{fill:var(--diagram-text);}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [data-look=\"neo\"].icon-shape .icon{fill:url(#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion-gradient);filter:drop-shadow( 1px 2px 2px rgba(185,185,185,1));}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [data-look=\"neo\"].icon-shape .icon-neo path{stroke:url(#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion-gradient);filter:drop-shadow( 1px 2px 2px rgba(185,185,185,1));}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .node rect,#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .node circle,#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .node ellipse,#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .node polygon,#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .node path{stroke-width:1.5px;}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .edgePath .path{stroke-width:1.5px;}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .label,#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .nodeLabel,#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .edgeLabel,#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .cluster-label,#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .messageText,#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .actor text{font-family:Geist,Inter,system-ui,sans-serif!important;font-weight:500!important;}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .nodeLabel,#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .cluster-label,#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .nodeLabel p,#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .cluster-label p{color:var(--diagram-text)!important;}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .nodeLabel .markdown-node-label,#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .nodeLabel .markdown-node-label p{color:var(--diagram-text)!important;}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .stateLabel text,#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .stateLabel{fill:var(--diagram-text)!important;font-weight:600!important;}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .edgeLabel{padding:0px 6px;background-color:var(--diagram-surface)!important;}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .edgeLabel rect.background,#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .edgeLabel rect{fill:var(--diagram-surface)!important;opacity:1!important;}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .edgeLabel .label text,#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .edgeLabel text{fill:var(--diagram-line)!important;}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .cluster rect{rx:4px;ry:4px;stroke-width:1px!important;stroke-dasharray:3,3!important;fill:transparent!important;}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .node rect,#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .node polygon,#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .stateGroup rect{rx:4px;ry:4px;}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion marker,#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion marker path{fill:var(--diagram-line)!important;stroke:var(--diagram-line)!important;}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .marker{fill:var(--diagram-line)!important;stroke:var(--diagram-line)!important;}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .actor{stroke-width:1.5px;}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .messageText,#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .messageText tspan{fill:var(--diagram-text)!important;}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .titleText{fill:var(--diagram-text)!important;font-weight:600!important;}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .note text,#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .note .nodeLabel{fill:var(--diagram-line)!important;color:var(--diagram-line)!important;}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .statediagram-cluster rect{fill:transparent!important;}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion .statediagram-state .divider{stroke:var(--diagram-border)!important;}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion :root{--mermaid-font-family:Geist,Inter,system-ui,-apple-system,sans-serif;}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [fill=\"#eef0fc\"]{fill:var(--diagram-node-bg)}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [stroke=\"#eef0fc\"]{stroke:var(--diagram-node-bg)}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [stop-color=\"#eef0fc\"]{stop-color:var(--diagram-node-bg)}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [fill=\"rgb(238, 240, 252)\"]{fill:var(--diagram-node-bg)}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [stroke=\"rgb(238, 240, 252)\"]{stroke:var(--diagram-node-bg)}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [stop-color=\"rgb(238, 240, 252)\"]{stop-color:var(--diagram-node-bg)}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [fill=\"#4948b8\"]{fill:var(--diagram-node-border)}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [stroke=\"#4948b8\"]{stroke:var(--diagram-node-border)}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [stop-color=\"#4948b8\"]{stop-color:var(--diagram-node-border)}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [fill=\"rgb(73, 72, 184)\"]{fill:var(--diagram-node-border)}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [stroke=\"rgb(73, 72, 184)\"]{stroke:var(--diagram-node-border)}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [stop-color=\"rgb(73, 72, 184)\"]{stop-color:var(--diagram-node-border)}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [fill=\"#c8cdf5\"]{fill:var(--diagram-accent-soft)}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [stroke=\"#c8cdf5\"]{stroke:var(--diagram-accent-soft)}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [stop-color=\"#c8cdf5\"]{stop-color:var(--diagram-accent-soft)}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [fill=\"rgb(200, 205, 245)\"]{fill:var(--diagram-accent-soft)}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [stroke=\"rgb(200, 205, 245)\"]{stroke:var(--diagram-accent-soft)}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [stop-color=\"rgb(200, 205, 245)\"]{stop-color:var(--diagram-accent-soft)}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [fill=\"#1f2127\"]{fill:var(--diagram-text)}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [stroke=\"#1f2127\"]{stroke:var(--diagram-text)}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [stop-color=\"#1f2127\"]{stop-color:var(--diagram-text)}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [fill=\"rgb(31, 33, 39)\"]{fill:var(--diagram-text)}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [stroke=\"rgb(31, 33, 39)\"]{stroke:var(--diagram-text)}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [stop-color=\"rgb(31, 33, 39)\"]{stop-color:var(--diagram-text)}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [fill=\"#000000\"]{fill:var(--diagram-text)}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [stroke=\"#000000\"]{stroke:var(--diagram-text)}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [stop-color=\"#000000\"]{stop-color:var(--diagram-text)}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [fill=\"rgb(0, 0, 0)\"]{fill:var(--diagram-text)}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [stroke=\"rgb(0, 0, 0)\"]{stroke:var(--diagram-text)}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [stop-color=\"rgb(0, 0, 0)\"]{stop-color:var(--diagram-text)}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [fill=\"#56595e\"]{fill:var(--diagram-line)}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [stroke=\"#56595e\"]{stroke:var(--diagram-line)}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [stop-color=\"#56595e\"]{stop-color:var(--diagram-line)}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [fill=\"rgb(86, 89, 94)\"]{fill:var(--diagram-line)}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [stroke=\"rgb(86, 89, 94)\"]{stroke:var(--diagram-line)}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [stop-color=\"rgb(86, 89, 94)\"]{stop-color:var(--diagram-line)}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [fill=\"#fafbfc\"]{fill:var(--diagram-surface)}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [stroke=\"#fafbfc\"]{stroke:var(--diagram-surface)}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [stop-color=\"#fafbfc\"]{stop-color:var(--diagram-surface)}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [fill=\"rgb(250, 251, 252)\"]{fill:var(--diagram-surface)}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [stroke=\"rgb(250, 251, 252)\"]{stroke:var(--diagram-surface)}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [stop-color=\"rgb(250, 251, 252)\"]{stop-color:var(--diagram-surface)}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [fill=\"#f3f4f6\"]{fill:var(--diagram-surface-alt)}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [stroke=\"#f3f4f6\"]{stroke:var(--diagram-surface-alt)}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [stop-color=\"#f3f4f6\"]{stop-color:var(--diagram-surface-alt)}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [fill=\"rgb(243, 244, 246)\"]{fill:var(--diagram-surface-alt)}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [stroke=\"rgb(243, 244, 246)\"]{stroke:var(--diagram-surface-alt)}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [stop-color=\"rgb(243, 244, 246)\"]{stop-color:var(--diagram-surface-alt)}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [fill=\"#c4c8cd\"]{fill:var(--diagram-border)}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [stroke=\"#c4c8cd\"]{stroke:var(--diagram-border)}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [stop-color=\"#c4c8cd\"]{stop-color:var(--diagram-border)}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [fill=\"rgb(196, 200, 205)\"]{fill:var(--diagram-border)}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [stroke=\"rgb(196, 200, 205)\"]{stroke:var(--diagram-border)}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [stop-color=\"rgb(196, 200, 205)\"]{stop-color:var(--diagram-border)}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [fill=\"#e5e7eb\"]{fill:var(--diagram-border)}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [stroke=\"#e5e7eb\"]{stroke:var(--diagram-border)}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [stop-color=\"#e5e7eb\"]{stop-color:var(--diagram-border)}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [fill=\"rgb(229, 231, 235)\"]{fill:var(--diagram-border)}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [stroke=\"rgb(229, 231, 235)\"]{stroke:var(--diagram-border)}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [stop-color=\"rgb(229, 231, 235)\"]{stop-color:var(--diagram-border)}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [fill=\"#e0e0e0\"]{fill:var(--diagram-border)}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [stroke=\"#e0e0e0\"]{stroke:var(--diagram-border)}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [stop-color=\"#e0e0e0\"]{stop-color:var(--diagram-border)}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [fill=\"rgb(224, 224, 224)\"]{fill:var(--diagram-border)}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [stroke=\"rgb(224, 224, 224)\"]{stroke:var(--diagram-border)}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [stop-color=\"rgb(224, 224, 224)\"]{stop-color:var(--diagram-border)}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [fill=\"#EDF2AE\"]{fill:var(--diagram-surface)}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [stroke=\"#EDF2AE\"]{stroke:var(--diagram-surface)}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [stop-color=\"#EDF2AE\"]{stop-color:var(--diagram-surface)}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [fill=\"rgb(237, 242, 174)\"]{fill:var(--diagram-surface)}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [stroke=\"rgb(237, 242, 174)\"]{stroke:var(--diagram-surface)}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [stop-color=\"rgb(237, 242, 174)\"]{stop-color:var(--diagram-surface)}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [fill=\"#fff5ad\"]{fill:var(--diagram-surface)}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [stroke=\"#fff5ad\"]{stroke:var(--diagram-surface)}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [stop-color=\"#fff5ad\"]{stop-color:var(--diagram-surface)}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [fill=\"rgb(255, 245, 173)\"]{fill:var(--diagram-surface)}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [stroke=\"rgb(255, 245, 173)\"]{stroke:var(--diagram-surface)}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [stop-color=\"rgb(255, 245, 173)\"]{stop-color:var(--diagram-surface)}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [fill=\"#666\"]{fill:var(--diagram-border)}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [stroke=\"#666\"]{stroke:var(--diagram-border)}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [stop-color=\"#666\"]{stop-color:var(--diagram-border)}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [fill=\"rgb(0, 6, 102)\"]{fill:var(--diagram-border)}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [stroke=\"rgb(0, 6, 102)\"]{stroke:var(--diagram-border)}#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion [stop-color=\"rgb(0, 6, 102)\"]{stop-color:var(--diagram-border)}\u003C\u002Fstyle>\u003Cg>\u003Cmarker id=\"ill-0-snt-2nde-sg-photo-numerique-hdr-fusion_flowchart-v2-pointEnd\" class=\"marker flowchart-v2\" viewBox=\"0 0 10 10\" refX=\"5\" refY=\"5\" markerUnits=\"userSpaceOnUse\" markerWidth=\"8\" markerHeight=\"8\" orient=\"auto\">\u003Cpath d=\"M 0 0 L 10 5 L 0 10 z\" class=\"arrowMarkerPath\" style=\"stroke-width: 1; stroke-dasharray: 1, 0;\"\u002F>\u003C\u002Fmarker>\u003Cmarker id=\"ill-0-snt-2nde-sg-photo-numerique-hdr-fusion_flowchart-v2-pointStart\" class=\"marker flowchart-v2\" viewBox=\"0 0 10 10\" refX=\"4.5\" refY=\"5\" markerUnits=\"userSpaceOnUse\" markerWidth=\"8\" markerHeight=\"8\" orient=\"auto\">\u003Cpath d=\"M 0 5 L 10 10 L 10 0 z\" class=\"arrowMarkerPath\" style=\"stroke-width: 1; stroke-dasharray: 1, 0;\"\u002F>\u003C\u002Fmarker>\u003Cmarker id=\"ill-0-snt-2nde-sg-photo-numerique-hdr-fusion_flowchart-v2-pointEnd-margin\" class=\"marker flowchart-v2\" viewBox=\"0 0 11.5 14\" refX=\"11.5\" refY=\"7\" markerUnits=\"userSpaceOnUse\" markerWidth=\"10.5\" markerHeight=\"14\" orient=\"auto\">\u003Cpath d=\"M 0 0 L 11.5 7 L 0 14 z\" class=\"arrowMarkerPath\" style=\"stroke-width: 0; stroke-dasharray: 1, 0;\"\u002F>\u003C\u002Fmarker>\u003Cmarker id=\"ill-0-snt-2nde-sg-photo-numerique-hdr-fusion_flowchart-v2-pointStart-margin\" class=\"marker flowchart-v2\" viewBox=\"0 0 11.5 14\" refX=\"1\" refY=\"7\" markerUnits=\"userSpaceOnUse\" markerWidth=\"11.5\" markerHeight=\"14\" orient=\"auto\">\u003Cpolygon points=\"0,7 11.5,14 11.5,0\" class=\"arrowMarkerPath\" style=\"stroke-width: 0; stroke-dasharray: 1, 0;\"\u002F>\u003C\u002Fmarker>\u003Cmarker id=\"ill-0-snt-2nde-sg-photo-numerique-hdr-fusion_flowchart-v2-circleEnd\" class=\"marker flowchart-v2\" viewBox=\"0 0 10 10\" refX=\"11\" refY=\"5\" markerUnits=\"userSpaceOnUse\" markerWidth=\"11\" markerHeight=\"11\" orient=\"auto\">\u003Ccircle cx=\"5\" cy=\"5\" r=\"5\" class=\"arrowMarkerPath\" style=\"stroke-width: 1; stroke-dasharray: 1, 0;\"\u002F>\u003C\u002Fmarker>\u003Cmarker id=\"ill-0-snt-2nde-sg-photo-numerique-hdr-fusion_flowchart-v2-circleStart\" class=\"marker flowchart-v2\" viewBox=\"0 0 10 10\" refX=\"-1\" refY=\"5\" markerUnits=\"userSpaceOnUse\" markerWidth=\"11\" markerHeight=\"11\" orient=\"auto\">\u003Ccircle cx=\"5\" cy=\"5\" r=\"5\" class=\"arrowMarkerPath\" style=\"stroke-width: 1; stroke-dasharray: 1, 0;\"\u002F>\u003C\u002Fmarker>\u003Cmarker id=\"ill-0-snt-2nde-sg-photo-numerique-hdr-fusion_flowchart-v2-circleEnd-margin\" class=\"marker flowchart-v2\" viewBox=\"0 0 10 10\" refY=\"5\" refX=\"12.25\" markerUnits=\"userSpaceOnUse\" markerWidth=\"14\" markerHeight=\"14\" orient=\"auto\">\u003Ccircle cx=\"5\" cy=\"5\" r=\"5\" class=\"arrowMarkerPath\" style=\"stroke-width: 0; stroke-dasharray: 1, 0;\"\u002F>\u003C\u002Fmarker>\u003Cmarker id=\"ill-0-snt-2nde-sg-photo-numerique-hdr-fusion_flowchart-v2-circleStart-margin\" class=\"marker flowchart-v2\" viewBox=\"0 0 10 10\" refX=\"-2\" refY=\"5\" markerUnits=\"userSpaceOnUse\" markerWidth=\"14\" markerHeight=\"14\" orient=\"auto\">\u003Ccircle cx=\"5\" cy=\"5\" r=\"5\" class=\"arrowMarkerPath\" style=\"stroke-width: 0; stroke-dasharray: 1, 0;\"\u002F>\u003C\u002Fmarker>\u003Cmarker id=\"ill-0-snt-2nde-sg-photo-numerique-hdr-fusion_flowchart-v2-crossEnd\" class=\"marker cross flowchart-v2\" viewBox=\"0 0 11 11\" refX=\"12\" refY=\"5.2\" markerUnits=\"userSpaceOnUse\" markerWidth=\"11\" markerHeight=\"11\" orient=\"auto\">\u003Cpath d=\"M 1,1 l 9,9 M 10,1 l -9,9\" class=\"arrowMarkerPath\" style=\"stroke-width: 2; stroke-dasharray: 1, 0;\"\u002F>\u003C\u002Fmarker>\u003Cmarker id=\"ill-0-snt-2nde-sg-photo-numerique-hdr-fusion_flowchart-v2-crossStart\" class=\"marker cross flowchart-v2\" viewBox=\"0 0 11 11\" refX=\"-1\" refY=\"5.2\" markerUnits=\"userSpaceOnUse\" markerWidth=\"11\" markerHeight=\"11\" orient=\"auto\">\u003Cpath d=\"M 1,1 l 9,9 M 10,1 l -9,9\" class=\"arrowMarkerPath\" style=\"stroke-width: 2; stroke-dasharray: 1, 0;\"\u002F>\u003C\u002Fmarker>\u003Cmarker id=\"ill-0-snt-2nde-sg-photo-numerique-hdr-fusion_flowchart-v2-crossEnd-margin\" class=\"marker cross flowchart-v2\" viewBox=\"0 0 15 15\" refX=\"17.7\" refY=\"7.5\" markerUnits=\"userSpaceOnUse\" markerWidth=\"12\" markerHeight=\"12\" orient=\"auto\">\u003Cpath d=\"M 1,1 L 14,14 M 1,14 L 14,1\" class=\"arrowMarkerPath\" style=\"stroke-width: 2.5;\"\u002F>\u003C\u002Fmarker>\u003Cmarker id=\"ill-0-snt-2nde-sg-photo-numerique-hdr-fusion_flowchart-v2-crossStart-margin\" class=\"marker cross flowchart-v2\" viewBox=\"0 0 15 15\" refX=\"-3.5\" refY=\"7.5\" markerUnits=\"userSpaceOnUse\" markerWidth=\"12\" markerHeight=\"12\" orient=\"auto\">\u003Cpath d=\"M 1,1 L 14,14 M 1,14 L 14,1\" class=\"arrowMarkerPath\" style=\"stroke-width: 2.5; stroke-dasharray: 1, 0;\"\u002F>\u003C\u002Fmarker>\u003Cg class=\"root\">\u003Cg class=\"clusters\"\u002F>\u003Cg class=\"edgePaths\">\u003Cpath d=\"M87.32,61L87.32,65.667C87.32,70.333,87.32,79.667,104.359,89.293C121.397,98.919,155.473,108.838,172.512,113.797L189.55,118.757\" id=\"ill-0-snt-2nde-sg-photo-numerique-hdr-fusion-L_A_H_0\" class=\"edge-thickness-normal edge-pattern-solid edge-thickness-normal edge-pattern-solid flowchart-link\" style=\";\" data-edge=\"true\" data-et=\"edge\" data-id=\"L_A_H_0\" data-points=\"W3sieCI6ODcuMzIwMzEyNSwieSI6NjF9LHsieCI6ODcuMzIwMzEyNSwieSI6ODl9LHsieCI6MTkzLjM5MDYyNSwieSI6MTE5Ljg3NDg0MzUyODMzMTgxfV0=\" data-look=\"classic\" marker-end=\"url(#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion_flowchart-v2-pointEnd)\"\u002F>\u003Cpath d=\"M274.555,61L274.555,65.667C274.555,70.333,274.555,79.667,274.555,88.333C274.555,97,274.555,105,274.555,109L274.555,113\" id=\"ill-0-snt-2nde-sg-photo-numerique-hdr-fusion-L_B_H_0\" class=\"edge-thickness-normal edge-pattern-solid edge-thickness-normal edge-pattern-solid flowchart-link\" style=\";\" data-edge=\"true\" data-et=\"edge\" data-id=\"L_B_H_0\" data-points=\"W3sieCI6Mjc0LjU1NDY4NzUsInkiOjYxfSx7IngiOjI3NC41NTQ2ODc1LCJ5Ijo4OX0seyJ4IjoyNzQuNTU0Njg3NSwieSI6MTE3fV0=\" data-look=\"classic\" marker-end=\"url(#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion_flowchart-v2-pointEnd)\"\u002F>\u003Cpath d=\"M456.438,61L456.438,65.667C456.438,70.333,456.438,79.667,440.29,89.172C424.142,98.677,391.846,108.354,375.698,113.193L359.55,118.032\" id=\"ill-0-snt-2nde-sg-photo-numerique-hdr-fusion-L_C_H_0\" class=\"edge-thickness-normal edge-pattern-solid edge-thickness-normal edge-pattern-solid flowchart-link\" style=\";\" data-edge=\"true\" data-et=\"edge\" data-id=\"L_C_H_0\" data-points=\"W3sieCI6NDU2LjQzNzUsInkiOjYxfSx7IngiOjQ1Ni40Mzc1LCJ5Ijo4OX0seyJ4IjozNTUuNzE4NzUsInkiOjExOS4xNzk3MTczNjYwOTI1Mn1d\" data-look=\"classic\" marker-end=\"url(#ill-0-snt-2nde-sg-photo-numerique-hdr-fusion_flowchart-v2-pointEnd)\"\u002F>\u003C\u002Fg>\u003Cg class=\"edgeLabels\">\u003Cg class=\"edgeLabel\">\u003Cg class=\"label\" data-id=\"L_A_H_0\" transform=\"translate(0, 0)\">\u003Ctext y=\"-10.1\" text-anchor=\"middle\">\u003Ctspan class=\"text-outer-tspan row\" x=\"0\" y=\"-0.1em\" dy=\"1.1em\" text-anchor=\"middle\"\u002F>\u003C\u002Ftext>\u003C\u002Fg>\u003C\u002Fg>\u003Cg>\u003Crect class=\"background\" style=\"stroke: none\"\u002F>\u003C\u002Fg>\u003Cg class=\"edgeLabel\">\u003Cg class=\"label\" data-id=\"L_B_H_0\" transform=\"translate(0, 0)\">\u003Ctext y=\"-10.1\" text-anchor=\"middle\">\u003Ctspan class=\"text-outer-tspan row\" x=\"0\" y=\"-0.1em\" dy=\"1.1em\" text-anchor=\"middle\"\u002F>\u003C\u002Ftext>\u003C\u002Fg>\u003C\u002Fg>\u003Cg>\u003Crect class=\"background\" style=\"stroke: none\"\u002F>\u003C\u002Fg>\u003Cg class=\"edgeLabel\">\u003Cg class=\"label\" data-id=\"L_C_H_0\" transform=\"translate(0, 0)\">\u003Ctext y=\"-10.1\" text-anchor=\"middle\">\u003Ctspan class=\"text-outer-tspan row\" x=\"0\" y=\"-0.1em\" dy=\"1.1em\" text-anchor=\"middle\"\u002F>\u003C\u002Ftext>\u003C\u002Fg>\u003C\u002Fg>\u003Cg>\u003Crect class=\"background\" style=\"stroke: none\"\u002F>\u003C\u002Fg>\u003C\u002Fg>\u003Cg class=\"nodes\">\u003Cg class=\"node default\" id=\"ill-0-snt-2nde-sg-photo-numerique-hdr-fusion-flowchart-A-0\" data-look=\"classic\" transform=\"translate(87.3203125, 34.5)\">\u003Crect class=\"basic label-container\" style=\"\" x=\"-79.3203125\" y=\"-22.5\" width=\"158.640625\" height=\"45\"\u002F>\u003Cg class=\"label\" style=\"\" transform=\"translate(-47.3203125, -10.5)\">\u003Crect\u002F>\u003CforeignObject width=\"94.640625\" height=\"21\">\u003Cdiv xmlns=\"http:\u002F\u002Fwww.w3.org\u002F1999\u002Fxhtml\" style=\"display: table-cell; white-space: nowrap; line-height: 1.5; max-width: 200px; text-align: center;\">\u003Cspan class=\"nodeLabel\">\u003Cp>Sous-exposée\u003C\u002Fp>\u003C\u002Fspan>\u003C\u002Fdiv>\u003C\u002FforeignObject>\u003C\u002Fg>\u003C\u002Fg>\u003Cg class=\"node default\" id=\"ill-0-snt-2nde-sg-photo-numerique-hdr-fusion-flowchart-B-1\" data-look=\"classic\" transform=\"translate(274.5546875, 34.5)\">\u003Crect class=\"basic label-container\" style=\"\" x=\"-59.9140625\" y=\"-22.5\" width=\"119.828125\" height=\"45\"\u002F>\u003Cg class=\"label\" style=\"\" transform=\"translate(-27.9140625, -10.5)\">\u003Crect\u002F>\u003CforeignObject width=\"55.828125\" height=\"21\">\u003Cdiv xmlns=\"http:\u002F\u002Fwww.w3.org\u002F1999\u002Fxhtml\" style=\"display: table-cell; white-space: nowrap; line-height: 1.5; max-width: 200px; text-align: center;\">\u003Cspan class=\"nodeLabel\">\u003Cp>Normale\u003C\u002Fp>\u003C\u002Fspan>\u003C\u002Fdiv>\u003C\u002FforeignObject>\u003C\u002Fg>\u003C\u002Fg>\u003Cg class=\"node default\" id=\"ill-0-snt-2nde-sg-photo-numerique-hdr-fusion-flowchart-C-2\" data-look=\"classic\" transform=\"translate(456.4375, 34.5)\">\u003Crect class=\"basic label-container\" style=\"\" x=\"-73.96875\" y=\"-22.5\" width=\"147.9375\" height=\"45\"\u002F>\u003Cg class=\"label\" style=\"\" transform=\"translate(-41.96875, -10.5)\">\u003Crect\u002F>\u003CforeignObject width=\"83.9375\" height=\"21\">\u003Cdiv xmlns=\"http:\u002F\u002Fwww.w3.org\u002F1999\u002Fxhtml\" style=\"display: table-cell; white-space: nowrap; line-height: 1.5; max-width: 200px; text-align: center;\">\u003Cspan class=\"nodeLabel\">\u003Cp>Sur-exposée\u003C\u002Fp>\u003C\u002Fspan>\u003C\u002Fdiv>\u003C\u002FforeignObject>\u003C\u002Fg>\u003C\u002Fg>\u003Cg class=\"node default\" id=\"ill-0-snt-2nde-sg-photo-numerique-hdr-fusion-flowchart-H-3\" data-look=\"classic\" transform=\"translate(274.5546875, 143.5)\">\u003Crect class=\"basic label-container\" style=\"\" x=\"-81.1640625\" y=\"-22.5\" width=\"162.328125\" height=\"45\"\u002F>\u003Cg class=\"label\" style=\"\" transform=\"translate(-49.1640625, -10.5)\">\u003Crect\u002F>\u003CforeignObject width=\"98.328125\" height=\"21\">\u003Cdiv xmlns=\"http:\u002F\u002Fwww.w3.org\u002F1999\u002Fxhtml\" style=\"display: table-cell; white-space: nowrap; line-height: 1.5; max-width: 200px; text-align: center;\">\u003Cspan class=\"nodeLabel\">\u003Cp>HDR fusionnée\u003C\u002Fp>\u003C\u002Fspan>\u003C\u002Fdiv>\u003C\u002FforeignObject>\u003C\u002Fg>\u003C\u002Fg>\u003C\u002Fg>\u003C\u002Fg>\u003C\u002Fg>\u003Cdefs>\u003Cfilter id=\"ill-0-snt-2nde-sg-photo-numerique-hdr-fusion-drop-shadow\" height=\"130%\" width=\"130%\">\u003CfeDropShadow dx=\"4\" dy=\"4\" stdDeviation=\"0\" flood-opacity=\"0.06\" flood-color=\"#000000\"\u002F>\u003C\u002Ffilter>\u003C\u002Fdefs>\u003Cdefs>\u003Cfilter id=\"ill-0-snt-2nde-sg-photo-numerique-hdr-fusion-drop-shadow-small\" height=\"150%\" width=\"150%\">\u003CfeDropShadow dx=\"2\" dy=\"2\" stdDeviation=\"0\" flood-opacity=\"0.06\" flood-color=\"#000000\"\u002F>\u003C\u002Ffilter>\u003C\u002Fdefs>\u003ClinearGradient id=\"ill-0-snt-2nde-sg-photo-numerique-hdr-fusion-gradient\" gradientUnits=\"objectBoundingBox\" x1=\"0%\" y1=\"0%\" x2=\"100%\" y2=\"0%\">\u003Cstop offset=\"0%\" stop-color=\"#4948b8\" stop-opacity=\"1\"\u002F>\u003Cstop offset=\"100%\" stop-color=\"#c4c8cd\" stop-opacity=\"1\"\u002F>\u003C\u002FlinearGradient>\u003C\u002Fsvg>",[594,1365,1367],{"id":1366},"le-débruitage","Le débruitage",[599,1369,1370,1371,1374,1375,1378],{},"En basse lumière, chaque photosite reçoit peu de photons. Les mesures sont\n",[603,1372,1373],{},"bruitées"," : des pixels aléatoirement trop clairs ou trop sombres apparaissent.\nUn algorithme de ",[603,1376,1377],{},"débruitage"," lisse l'image en moyennant les zones homogènes\ntout en préservant les contours.",[1147,1380,1381],{},[599,1382,1383,1384,1387],{},"Trop de débruitage ",[603,1385,1386],{},"efface les détails",". La frontière entre « image lissée »\net « image qui ressemble à une peinture » est mince. Les smartphones poussent\nparfois trop loin pour faire de jolies miniatures.",[594,1389,1391],{"id":1390},"démosaïçage-et-autres-traitements-en-amont","Démosaïçage et autres traitements en amont",[599,1393,1394,1395,1398,1399,1402,1403,1406,1407,1410],{},"Avant tous ces réglages, un algorithme essentiel intervient : le\n",[603,1396,1397],{},"démosaïçage",". Rappelez-vous : chaque photosite ne mesure ",[603,1400,1401],{},"qu'une"," couleur\nparmi R, G, B. Pour produire une image dont ",[603,1404,1405],{},"chaque pixel"," porte les trois\ncomposantes, l'appareil ",[603,1408,1409],{},"interpole"," les valeurs manquantes à partir des\nvoisins.",[639,1412,1413],{},[599,1414,1415],{},"Sans démosaïçage, vous obtiendriez une image en mosaïque rouge\u002Fvert\u002Fbleu. La\nphoto « lisse » que vous voyez est déjà le résultat d'un calcul.",[594,1417,1419],{"id":1418},"vérification-de-compréhension","Vérification de compréhension",[718,1421,1424,1429],{"correct":935,"explanation":1422,"slug":1423},"Le HDR (High Dynamic Range) fusionne plusieurs photos d'expositions différentes en une seule image.","algorithmes-photo-c2",[724,1425,1426],{"v-slot:question":726},[599,1427,1428],{},"Quel algorithme combine plusieurs prises de vue successives ?",[724,1430,1431],{"v-slot:choices":726},[733,1432,1433,1436,1438,1441],{},[736,1434,1435],{},"L’autofocus",[736,1437,1367],{},[736,1439,1440],{},"Le HDR",[736,1442,1443],{},"La balance des blancs",[718,1445,1448,1453],{"correct":852,"explanation":1446,"slug":1447},"Le démosaïçage interpole les composantes manquantes à partir des voisins, puisque chaque photosite ne mesure qu'une seule couleur.","algorithmes-photo-c3",[724,1449,1450],{"v-slot:question":726},[599,1451,1452],{},"Le démosaïçage sert à :",[724,1454,1455],{"v-slot:choices":726},[733,1456,1457,1460,1463],{},[736,1458,1459],{},"Compresser l’image",[736,1461,1462],{},"Reconstruire les trois composantes RGB de chaque pixel",[736,1464,1465],{},"Détecter les visages",[594,1467,1172],{"id":1171},[599,1469,1470,1471,1474,1475,1478,1479,1482,1483,1486],{},"Les ",[603,1472,1473],{},"smartphones modernes"," entrent dans une autre catégorie : la\n",[846,1476,1477],{},"photographie computationnelle",". Pour un seul déclenchement, ils combinent\nplusieurs poses, du ",[846,1480,1481],{},"machine learning"," pour reconnaître la scène, et des\nréglages adaptés au sujet. Le « grain » d'une photo de smartphone n'a presque\nplus rien à voir avec ce que le capteur a réellement mesuré — il est en\ngrande partie ",[603,1484,1485],{},"calculé"," pour vous plaire.",{"title":726,"searchDepth":1181,"depth":1181,"links":1488},[1489,1490,1491,1492,1493,1494,1495,1496],{"id":596,"depth":1181,"text":597},{"id":1236,"depth":1181,"text":1237},{"id":1298,"depth":1181,"text":1299},{"id":1328,"depth":1181,"text":1329},{"id":1366,"depth":1181,"text":1367},{"id":1390,"depth":1181,"text":1391},{"id":1418,"depth":1181,"text":1419},{"id":1171,"depth":1181,"text":1172},"Autofocus, balance des blancs, HDR, débruitage — la photo numérique est calculée bien avant d'être enregistrée.",{},[1500,1502,1504],{"slug":1277,"kind":1197,"question":1282,"choices":1501,"correct":852,"multi":1199,"explanation":1276},[1289,1292,1295],{"slug":1423,"kind":1197,"question":1428,"choices":1503,"correct":935,"multi":1199,"explanation":1422},[1435,1367,1440,1443],{"slug":1447,"kind":1197,"question":1452,"choices":1505,"correct":852,"multi":1199,"explanation":1446},[1459,1462,1465],{"title":173,"description":1497},"sPCL-zFkOtC3Hg86EC1O5kwYEtVrtWXZZjLf9DkqxXU",{"id":1509,"title":177,"bo":1510,"body":1512,"description":2079,"eval":1191,"extension":1192,"labo":1191,"meta":2080,"navigation":1194,"path":178,"quizzes":2081,"readingTime":1204,"seo":2088,"stem":179,"tp":1191,"__hash__":2089},"cours\u002F0.snt-2nde\u002Fsg-photo-numerique\u002F3.metadonnees-exif.md",[1511],"SG01",{"type":591,"value":1513,"toc":2070},[1514,1516,1538,1553,1555,1559,1581,1597,1601,1604,1685,1688,1693,1697,1725,1889,1911,1915,1926,1942,1945,1967,1984,1988,1991,2014,2036,2058,2060,2066],[594,1515,597],{"id":596},[599,1517,1518,1519,1521,1522,1525,1526,1529,1530,1533,1534,1537],{},"Vous prenez une photo. Vous ne voyez à l'écran qu'une ",[603,1520,795],{},". Mais le\nfichier qui vient d'être enregistré contient bien plus : la ",[603,1523,1524],{},"date"," exacte\nde la prise, le ",[603,1527,1528],{},"modèle"," de l'appareil, les ",[603,1531,1532],{},"réglages"," utilisés, et\nparfois — souvent même — les ",[603,1535,1536],{},"coordonnées GPS"," du lieu où vous étiez.",[599,1539,1540,1541,1544,1545,1548,1549,1552],{},"Ces informations s'appellent les ",[603,1542,1543],{},"métadonnées EXIF",", pour ",[846,1546,1547],{},"Exchangeable\nImage File Format",". Elles sont ",[603,1550,1551],{},"invisibles à l'œil",", mais facilement lisibles\npar n'importe quel logiciel adapté. Comprendre ce qu'elles contiennent est\nindispensable pour maîtriser ce que vous publiez sur Internet.",[622,1554],{"code":1511},[594,1556,1558],{"id":1557},"une-métadonnée-cest-quoi","Une métadonnée, c'est quoi ?",[599,1560,1561,1562,1565,1566,1569,1570,1573,1574,1577,1578,620],{},"Une ",[603,1563,1564],{},"métadonnée"," est une ",[603,1567,1568],{},"donnée qui décrit une autre donnée",". Pour une\nphoto, la donnée principale est l'image elle-même (la grille de pixels) ; les\nmétadonnées sont les informations sur ",[603,1571,1572],{},"les conditions de prise de vue",", sur\n",[603,1575,1576],{},"l'appareil",", et sur ",[603,1579,1580],{},"l'environnement",[639,1582,1583],{},[599,1584,1585,1586,1589,1590,1592,1593,1596],{},"Le préfixe ",[846,1587,1588],{},"méta-"," vient du grec et signifie « au-delà ». Une ",[603,1591,1564],{},"\nest ce qu'on dit ",[603,1594,1595],{},"autour"," d'une donnée, sans en faire partie directement.",[594,1598,1600],{"id":1599},"quatre-métadonnées-emblématiques","Quatre métadonnées emblématiques",[599,1602,1603],{},"Voici les quatre métadonnées EXIF que vous devez savoir reconnaître :",[659,1605,1606,1619],{},[662,1607,1608],{},[665,1609,1610,1613,1616],{},[668,1611,1612],{},"Métadonnée",[668,1614,1615],{},"Exemple de valeur",[668,1617,1618],{},"Utilité",[675,1620,1621,1636,1651,1670],{},[665,1622,1623,1628,1633],{},[680,1624,1625],{},[603,1626,1627],{},"Date & heure",[680,1629,1630],{},[805,1631,1632],{},"2026:03:14 17:42:08",[680,1634,1635],{},"Trier ses photos, dater un événement.",[665,1637,1638,1643,1648],{},[680,1639,1640],{},[603,1641,1642],{},"Coordonnées GPS",[680,1644,1645],{},[805,1646,1647],{},"48.8584° N, 2.2945° E",[680,1649,1650],{},"Géolocaliser le lieu de prise.",[665,1652,1653,1658,1667],{},[680,1654,1655],{},[603,1656,1657],{},"Modèle d'appareil",[680,1659,1660,1663,1664],{},[805,1661,1662],{},"iPhone 15 Pro"," ou ",[805,1665,1666],{},"Canon EOS R6",[680,1668,1669],{},"Identifier la source matérielle.",[665,1671,1672,1677,1682],{},[680,1673,1674],{},[603,1675,1676],{},"Ouverture \u002F vitesse \u002F ISO",[680,1678,1679],{},[805,1680,1681],{},"f\u002F2.8 — 1\u002F200 s — ISO 400",[680,1683,1684],{},"Comprendre les choix techniques.",[599,1686,1687],{},"D'autres métadonnées existent (orientation, balance des blancs, distance de\nmise au point, logiciel de retouche utilisé…), mais ces quatre-là sont les\nplus souvent citées.",[711,1689],{"alt":1690,"kind":714,"src":1691,"svg":1692},"Une photo de paysage avec une bulle latérale listant ses métadonnées EXIF : date 2026-03-14 17:42, GPS 48,85 N 2,29 E, iPhone 15 Pro, f\u002F2.8 1\u002F200s ISO 400","\u002Fillustrations\u002F0.snt-2nde\u002Fsg-photo-numerique\u002Fexif.svg","\u003Csvg class=\"illustration-svg\" xmlns=\"http:\u002F\u002Fwww.w3.org\u002F2000\u002Fsvg\" viewBox=\"0 0 480 280\" role=\"img\" aria-label=\"Une photo de paysage (cadre image, montagnes et soleil) reliée à une bulle latérale listant ses métadonnées EXIF : date 2026-03-14 17:42, GPS 48,85 N 2,29 E, appareil iPhone 15 Pro, réglages f sur 2,8, 1 sur 200 s, ISO 400.\">\n  \u003Ctitle>Une photo et ses métadonnées EXIF cachées\u003C\u002Ftitle>\n  \u003Cstyle>\n    .ex-frame   { fill: var(--diagram-surface-alt); stroke: var(--diagram-node-border); stroke-width: 2; }\n    .ex-sky     { fill: var(--diagram-surface); }\n    .ex-shape   { fill: var(--diagram-line); opacity: 0.5; }\n    .ex-sun     { fill: var(--diagram-node-border); opacity: 0.6; }\n    .ex-leader  { stroke: var(--diagram-line); stroke-width: 1.5; stroke-dasharray: 4 3; fill: none; }\n    .ex-bubble  { fill: var(--diagram-node-bg); stroke: var(--diagram-node-border); stroke-width: 1.5; }\n    .ex-eyebrow { fill: var(--diagram-line); font-family: 'JetBrains Mono', monospace; font-size: 10px; letter-spacing: 1.5px; }\n    .ex-key     { fill: var(--diagram-text); font-family: Geist, Inter, system-ui, sans-serif; font-size: 11px; font-weight: 600; }\n    .ex-val     { fill: var(--diagram-line); font-family: 'JetBrains Mono', monospace; font-size: 10.5px; }\n    .ex-cap     { fill: var(--diagram-line); font-family: Geist, Inter, system-ui, sans-serif; font-size: 11px; font-style: italic; }\n  \u003C\u002Fstyle>\n\n  \u003C!-- ░░ Photo de paysage (placeholder) ░░ -->\n  \u003Ctext x=\"30\" y=\"28\" class=\"ex-eyebrow\">CE QU'ON VOIT\u003C\u002Ftext>\n  \u003Crect x=\"30\" y=\"36\" width=\"200\" height=\"150\" rx=\"6\" class=\"ex-frame\"\u002F>\n  \u003CclipPath id=\"ex-clip\">\u003Crect x=\"32\" y=\"38\" width=\"196\" height=\"146\" rx=\"5\"\u002F>\u003C\u002FclipPath>\n  \u003Cg clip-path=\"url(#ex-clip)\">\n    \u003Crect x=\"32\" y=\"38\" width=\"196\" height=\"146\" class=\"ex-sky\"\u002F>\n    \u003C!-- soleil -->\n    \u003Ccircle cx=\"180\" cy=\"80\" r=\"18\" class=\"ex-sun\"\u002F>\n    \u003C!-- montagnes -->\n    \u003Cpolygon class=\"ex-shape\" points=\"32,184 90,108 140,184\"\u002F>\n    \u003Cpolygon class=\"ex-shape\" points=\"110,184 175,120 228,184\"\u002F>\n  \u003C\u002Fg>\n  \u003Ctext x=\"130\" y=\"204\" text-anchor=\"middle\" class=\"ex-cap\">l'image visible\u003C\u002Ftext>\n\n  \u003C!-- ░░ Lien vers les métadonnées invisibles ░░ -->\n  \u003Cpath class=\"ex-leader\" d=\"M 230 110 L 270 110\"\u002F>\n  \u003Ctext x=\"250\" y=\"100\" text-anchor=\"middle\" class=\"ex-eyebrow\" font-size=\"9\">+ caché\u003C\u002Ftext>\n\n  \u003C!-- ░░ Bulle latérale : métadonnées EXIF ░░ -->\n  \u003Crect x=\"272\" y=\"36\" width=\"186\" height=\"208\" rx=\"8\" class=\"ex-bubble\"\u002F>\n  \u003Ctext x=\"288\" y=\"62\" class=\"ex-eyebrow\">MÉTADONNÉES EXIF\u003C\u002Ftext>\n  \u003Cline x1=\"288\" y1=\"72\" x2=\"442\" y2=\"72\" stroke=\"var(--diagram-border)\" stroke-width=\"1\"\u002F>\n\n  \u003Ctext x=\"288\" y=\"96\"  class=\"ex-key\">Date\u003C\u002Ftext>\n  \u003Ctext x=\"288\" y=\"112\" class=\"ex-val\">2026-03-14 17:42\u003C\u002Ftext>\n\n  \u003Ctext x=\"288\" y=\"138\" class=\"ex-key\">GPS\u003C\u002Ftext>\n  \u003Ctext x=\"288\" y=\"154\" class=\"ex-val\">48,85° N  2,29° E\u003C\u002Ftext>\n\n  \u003Ctext x=\"288\" y=\"180\" class=\"ex-key\">Appareil\u003C\u002Ftext>\n  \u003Ctext x=\"288\" y=\"196\" class=\"ex-val\">iPhone 15 Pro\u003C\u002Ftext>\n\n  \u003Ctext x=\"288\" y=\"222\" class=\"ex-key\">Réglages\u003C\u002Ftext>\n  \u003Ctext x=\"288\" y=\"238\" class=\"ex-val\">f\u002F2.8  1\u002F200s  ISO 400\u003C\u002Ftext>\n\u003C\u002Fsvg>\n",[594,1694,1696],{"id":1695},"comment-les-consulter","Comment les consulter ?",[733,1698,1699,1705,1719],{},[736,1700,1701,1704],{},[603,1702,1703],{},"Sur ordinateur"," : un clic droit sur le fichier → « Propriétés » → onglet\n« Détails » (Windows) ou « Plus d'infos » (macOS).",[736,1706,1707,1710,1711,1718],{},[603,1708,1709],{},"En ligne"," : des services comme ",[1712,1713,1717],"a",{"href":1714,"rel":1715},"https:\u002F\u002Fexifinfo.org",[1716],"nofollow","exifinfo.org","\naffichent les métadonnées de n'importe quelle image téléversée.",[736,1720,1721,1724],{},[603,1722,1723],{},"Par programme"," : en Python, la bibliothèque PIL\u002FPillow permet d'y accéder.",[1726,1727,1730,1741],"card",{"icon":1728,"title":1729},"i-lucide-play","Démo enseignante",[599,1731,1732,1733,1736,1737,1740],{},"Le code ci-dessous (à observer, pas à reproduire) utilise la bibliothèque\n",[603,1734,1735],{},"PIL\u002FPillow"," pour lister les métadonnées EXIF d'une photo. Vous n'êtes pas\ncensés savoir l'écrire : retenez seulement le ",[603,1738,1739],{},"principe"," — une boucle qui\nparcourt les balises EXIF de l'image et les affiche.",[1742,1743,1747],"pre",{"className":1744,"code":1745,"language":1746,"meta":726,"style":726},"language-python shiki shiki-themes github-light github-light github-dark","from PIL import Image\nfrom PIL.ExifTags import TAGS\n\nimage = Image.open(\"photo.jpg\")\nexif = image.getexif()\n\nfor tag_id, valeur in exif.items():\n    nom = TAGS.get(tag_id, tag_id)\n    print(f\"{nom} : {valeur}\")\n","python",[805,1748,1749,1767,1782,1788,1806,1817,1822,1837,1851],{"__ignoreMap":726},[898,1750,1752,1756,1760,1763],{"class":1751,"line":1204},"line",[898,1753,1755],{"class":1754},"s8jYJ","from",[898,1757,1759],{"class":1758},"sBjJW"," PIL",[898,1761,1762],{"class":1754}," import",[898,1764,1766],{"class":1765},"sxrX7"," Image\n",[898,1768,1769,1771,1773,1776,1779],{"class":1751,"line":1181},[898,1770,1755],{"class":1754},[898,1772,1759],{"class":1758},[898,1774,1775],{"class":1765},".ExifTags ",[898,1777,1778],{"class":1754},"import",[898,1780,1781],{"class":1758}," TAGS\n",[898,1783,1785],{"class":1751,"line":1784},3,[898,1786,1787],{"emptyLinePlaceholder":1194},"\n",[898,1789,1791,1794,1796,1799,1803],{"class":1751,"line":1790},4,[898,1792,1793],{"class":1765},"image ",[898,1795,928],{"class":1754},[898,1797,1798],{"class":1765}," Image.open(",[898,1800,1802],{"class":1801},"sIIMD","\"photo.jpg\"",[898,1804,1805],{"class":1765},")\n",[898,1807,1809,1812,1814],{"class":1751,"line":1808},5,[898,1810,1811],{"class":1765},"exif ",[898,1813,928],{"class":1754},[898,1815,1816],{"class":1765}," image.getexif()\n",[898,1818,1820],{"class":1751,"line":1819},6,[898,1821,1787],{"emptyLinePlaceholder":1194},[898,1823,1825,1828,1831,1834],{"class":1751,"line":1824},7,[898,1826,1827],{"class":1754},"for",[898,1829,1830],{"class":1765}," tag_id, valeur ",[898,1832,1833],{"class":1754},"in",[898,1835,1836],{"class":1765}," exif.items():\n",[898,1838,1840,1843,1845,1848],{"class":1751,"line":1839},8,[898,1841,1842],{"class":1765},"    nom ",[898,1844,928],{"class":1754},[898,1846,1847],{"class":1758}," TAGS",[898,1849,1850],{"class":1765},".get(tag_id, tag_id)\n",[898,1852,1854,1857,1860,1863,1866,1869,1872,1875,1878,1880,1883,1885,1887],{"class":1751,"line":1853},9,[898,1855,1856],{"class":1758},"    print",[898,1858,1859],{"class":1765},"(",[898,1861,1862],{"class":1754},"f",[898,1864,1865],{"class":1801},"\"",[898,1867,1868],{"class":1758},"{",[898,1870,1871],{"class":1765},"nom",[898,1873,1874],{"class":1758},"}",[898,1876,1877],{"class":1801}," : ",[898,1879,1868],{"class":1758},[898,1881,1882],{"class":1765},"valeur",[898,1884,1874],{"class":1758},[898,1886,1865],{"class":1801},[898,1888,1805],{"class":1765},[718,1890,1893,1898],{"correct":852,"explanation":1891,"slug":1892},"Méta- signifie « au sujet de ». Une métadonnée décrit, contextualise ou complète une donnée principale.","metadonnees-exif-c1",[724,1894,1895],{"v-slot:question":726},[599,1896,1897],{},"Une métadonnée est :",[724,1899,1900],{"v-slot:choices":726},[733,1901,1902,1905,1908],{},[736,1903,1904],{},"Une donnée chiffrée",[736,1906,1907],{},"Une donnée qui en décrit une autre",[736,1909,1910],{},"Une donnée qui ne sert à rien",[594,1912,1914],{"id":1913},"lenjeu-de-confidentialité","L'enjeu de confidentialité",[599,1916,1917,1918,1921,1922,1925],{},"C'est le point le plus important du cours. Lorsque vous ",[603,1919,1920],{},"publiez"," une photo\nsur Internet (réseau social, site, mail), vous publiez souvent ",[603,1923,1924],{},"sans le\nsavoir"," ses métadonnées.",[1147,1927,1928],{},[599,1929,1930,1933,1934,1937,1938,1941],{},[603,1931,1932],{},"Conséquence directe"," : si la géolocalisation était activée, n'importe\nquelle personne ayant le fichier original peut ",[603,1935,1936],{},"savoir où"," la photo a été\nprise — à quelques mètres près. Et ",[603,1939,1940],{},"quand"," elle a été prise — à la seconde\nprès.",[599,1943,1944],{},"Quelques scénarios concrets :",[733,1946,1947,1953,1960],{},[736,1948,1949,1950,620],{},"Une photo de votre chambre publiée sur les réseaux peut révéler votre ",[603,1951,1952],{},"adresse",[736,1954,1955,1956,1959],{},"Une photo « de vacances » prise depuis la maison, c'est révéler ",[603,1957,1958],{},"que vous\nêtes en vacances"," et donc absent(e).",[736,1961,1962,1963,1966],{},"Un cliché anonyme partagé peut être ",[603,1964,1965],{},"rattaché"," au modèle exact de votre\nappareil.",[772,1968,1969],{},[599,1970,1971,1972,1975,1976,1979,1980,1983],{},"La plupart des grandes plateformes (Instagram, Facebook, X…) ",[603,1973,1974],{},"suppriment","\nles métadonnées EXIF à la publication, par défaut, depuis quelques années.\nMais ",[603,1977,1978],{},"pas"," les services de partage de fichiers bruts (Discord, mail,\nhébergeur d'images) ni les ",[603,1981,1982],{},"envois directs"," entre utilisateurs.",[594,1985,1987],{"id":1986},"bonnes-pratiques","Bonnes pratiques",[599,1989,1990],{},"Concrètement :",[825,1992,1993,1999,2008],{},[736,1994,1995,1998],{},[603,1996,1997],{},"Désactivez la géolocalisation des photos"," dans les réglages de votre\nsmartphone (ou activez-la seulement quand vous en avez besoin).",[736,2000,2001,2004,2005,620],{},[603,2002,2003],{},"Supprimez les EXIF"," avant de partager une photo sensible : un clic\ndroit → « Supprimer les propriétés » (Windows), ou un site comme\n",[805,2006,2007],{},"exifpurge.com",[736,2009,2010,2013],{},[603,2011,2012],{},"Méfiez-vous"," d'une photo trouvée sur Internet dont les EXIF sont\ncomplètes : c'est souvent qu'elle vient directement de quelqu'un qui n'y a\npas pensé.",[718,2015,2018,2023],{"correct":852,"explanation":2016,"slug":2017},"Les coordonnées GPS révèlent un lieu précis. C'est la métadonnée la plus sensible — date et appareil sont aussi des indices mais moins critiques.","metadonnees-exif-c2",[724,2019,2020],{"v-slot:question":726},[599,2021,2022],{},"Sur quel élément les métadonnées EXIF posent-elles un enjeu de confidentialité majeur ?",[724,2024,2025],{"v-slot:choices":726},[733,2026,2027,2030,2033],{},[736,2028,2029],{},"La résolution de l’image",[736,2031,2032],{},"La géolocalisation GPS",[736,2034,2035],{},"Le modèle d’appareil",[718,2037,2040,2045],{"correct":852,"explanation":2038,"slug":2039},"Les grandes plateformes suppriment les EXIF à la publication depuis quelques années — mais pas tous les canaux de partage. Mieux vaut ne pas s'y fier aveuglément.","metadonnees-exif-c3",[724,2041,2042],{"v-slot:question":726},[599,2043,2044],{},"Une photo publiée sur Instagram contient-elle ses EXIF d'origine ?",[724,2046,2047],{"v-slot:choices":726},[733,2048,2049,2052,2055],{},[736,2050,2051],{},"Oui, toujours",[736,2053,2054],{},"Non, Instagram les supprime par défaut",[736,2056,2057],{},"Seulement si l’auteur l’a demandé",[594,2059,1172],{"id":1171},[599,2061,2062,2063],{},"Les métadonnées EXIF ne concernent pas que la photographie. Tout fichier\nnumérique contient potentiellement des métadonnées : un document PDF (nom de\nl'auteur, logiciel utilisé), un fichier audio (titre, artiste, durée, taux\nd'échantillonnage), une vidéo (date, lieu, appareil). À chaque fois, la\nquestion est la même : ",[603,2064,2065],{},"que dit ce fichier de la personne qui l'a produit ?",[2067,2068,2069],"style",{},"html pre.shiki code .s8jYJ, html code.shiki .s8jYJ{--shiki-light:#D73A49;--shiki-default:#D73A49;--shiki-dark:#F97583}html pre.shiki code .sBjJW, html code.shiki .sBjJW{--shiki-light:#005CC5;--shiki-default:#005CC5;--shiki-dark:#79B8FF}html pre.shiki code .sxrX7, html code.shiki .sxrX7{--shiki-light:#24292E;--shiki-default:#24292E;--shiki-dark:#E1E4E8}html pre.shiki code .sIIMD, html code.shiki .sIIMD{--shiki-light:#032F62;--shiki-default:#032F62;--shiki-dark:#9ECBFF}html .light .shiki span {color: var(--shiki-light);background: var(--shiki-light-bg);font-style: var(--shiki-light-font-style);font-weight: var(--shiki-light-font-weight);text-decoration: var(--shiki-light-text-decoration);}html.light .shiki span {color: var(--shiki-light);background: var(--shiki-light-bg);font-style: var(--shiki-light-font-style);font-weight: var(--shiki-light-font-weight);text-decoration: var(--shiki-light-text-decoration);}html .default .shiki span {color: var(--shiki-default);background: var(--shiki-default-bg);font-style: var(--shiki-default-font-style);font-weight: var(--shiki-default-font-weight);text-decoration: var(--shiki-default-text-decoration);}html .shiki span {color: var(--shiki-default);background: var(--shiki-default-bg);font-style: var(--shiki-default-font-style);font-weight: var(--shiki-default-font-weight);text-decoration: var(--shiki-default-text-decoration);}html .dark .shiki span {color: var(--shiki-dark);background: var(--shiki-dark-bg);font-style: var(--shiki-dark-font-style);font-weight: var(--shiki-dark-font-weight);text-decoration: var(--shiki-dark-text-decoration);}html.dark .shiki span {color: var(--shiki-dark);background: var(--shiki-dark-bg);font-style: var(--shiki-dark-font-style);font-weight: var(--shiki-dark-font-weight);text-decoration: var(--shiki-dark-text-decoration);}",{"title":726,"searchDepth":1181,"depth":1181,"links":2071},[2072,2073,2074,2075,2076,2077,2078],{"id":596,"depth":1181,"text":597},{"id":1557,"depth":1181,"text":1558},{"id":1599,"depth":1181,"text":1600},{"id":1695,"depth":1181,"text":1696},{"id":1913,"depth":1181,"text":1914},{"id":1986,"depth":1181,"text":1987},{"id":1171,"depth":1181,"text":1172},"Les informations cachées dans un fichier image et leurs enjeux de confidentialité.",{},[2082,2084,2086],{"slug":1892,"kind":1197,"question":1897,"choices":2083,"correct":852,"multi":1199,"explanation":1891},[1904,1907,1910],{"slug":2017,"kind":1197,"question":2022,"choices":2085,"correct":852,"multi":1199,"explanation":2016},[2029,2032,2035],{"slug":2039,"kind":1197,"question":2044,"choices":2087,"correct":852,"multi":1199,"explanation":2038},[2051,2054,2057],{"title":177,"description":2079},"NuYf5Gi1XphnPbS5ul4wtjfGE54AVBraKwxHCpCnEng",{"id":2091,"title":181,"bo":2092,"body":2094,"description":3401,"eval":1191,"extension":1192,"labo":1191,"meta":3402,"navigation":1194,"path":182,"quizzes":3403,"readingTime":1204,"seo":3414,"stem":183,"tp":1191,"__hash__":3415},"cours\u002F0.snt-2nde\u002Fsg-photo-numerique\u002F4.traitement-rgb.md",[2093],"SG04",{"type":591,"value":2095,"toc":3389},[2096,2098,2105,2112,2114,2118,2121,2148,2163,2181,2210,2214,2217,2249,2256,2260,2267,2354,2361,2384,2508,2556,2560,2571,2578,2748,2754,2880,2922,2927,2931,2947,3025,3028,3050,3052,3077,3099,3131,3135,3150,3336,3338,3377,3379,3386],[594,2097,597],{"id":596},[599,2099,2100,2101,2104],{},"Un filtre Instagram, une retouche dans l'application Photos de votre\ntéléphone, un effet « noir et blanc » dans Snapchat : derrière chacun de ces\neffets, un programme ",[603,2102,2103],{},"modifie les couleurs des pixels"," un par un. Ce\nn'est pas magique — c'est trois petits calculs sur trois petits nombres,\nrépétés très vite.",[599,2106,2107,2108,2111],{},"Dans ce cours, vous allez écrire vous-même les calculs qui transforment\nune couleur. On reste à l'échelle d'",[603,2109,2110],{},"un seul pixel à la fois"," : c'est tout\nce qu'il faut pour comprendre comment fonctionne une retouche.",[622,2113],{"code":2093},[594,2115,2117],{"id":2116},"une-image-cest-une-grille-de-jauges","Une image, c'est une grille de jauges",[599,2119,2120],{},"Avant d'écrire du code, posons l'image mentale.",[639,2122,2123,2142],{},[599,2124,2125,2126,2129,2130,2133,2134,2137,2138,2141],{},"Une image numérique est une ",[603,2127,2128],{},"grille de petites cases"," — les pixels.\nChaque case porte ",[603,2131,2132],{},"trois jauges réglables"," : une rouge, une verte, une\nbleue. Chaque jauge va de ",[603,2135,2136],{},"0"," (éteinte) à ",[603,2139,2140],{},"255"," (à fond).",[599,2143,2144,2147],{},[603,2145,2146],{},"Modifier une image, c'est tourner les jauges",", case par case.",[599,2149,2150,2151,2154,2155,2158,2159,2162],{},"Une couleur de pixel s'écrit alors comme un trio de nombres. Par exemple\n",[805,2152,2153],{},"(255, 0, 0)"," signifie « jauge rouge à fond, vert à zéro, bleu à zéro » —\nc'est du rouge pur. ",[805,2156,2157],{},"(0, 0, 0)"," est noir (toutes les jauges éteintes),\n",[805,2160,2161],{},"(255, 255, 255)"," est blanc (toutes à fond).",[599,2164,2165,2166,2169,2170,610,2173,2176,2177,2180],{},"Dans tout ce cours, ",[603,2167,2168],{},"un pixel = trois nombres"," que l'on appelle ",[805,2171,2172],{},"r",[805,2174,2175],{},"g",",\n",[805,2178,2179],{},"b"," (pour rouge, vert, bleu). Aucune autre notation à connaître.",[718,2182,2185,2194],{"correct":852,"explanation":2183,"slug":2184},"La jauge verte est à fond (255), les deux autres sont éteintes (0). C'est du vert pur.","traitement-rgb-c1",[724,2186,2187],{"v-slot:question":726},[599,2188,2189,2190,2193],{},"Que représente le pixel ",[805,2191,2192],{},"(0, 255, 0)"," ?",[724,2195,2196],{"v-slot:choices":726},[733,2197,2198,2201,2204,2207],{},[736,2199,2200],{},"Du rouge pur",[736,2202,2203],{},"Du vert pur",[736,2205,2206],{},"Du bleu pur",[736,2208,2209],{},"Du noir",[594,2211,2213],{"id":2212},"transformer-un-pixel-lidée-générale","Transformer un pixel — l'idée générale",[599,2215,2216],{},"Un programme de retouche fait toujours la même chose pour un pixel :",[825,2218,2219,2231,2243],{},[736,2220,2221,2224,2225,610,2227,610,2229,620],{},[603,2222,2223],{},"Lire"," ses trois nombres ",[805,2226,2172],{},[805,2228,2175],{},[805,2230,2179],{},[736,2232,2233,2236,2237,610,2239,610,2241,620],{},[603,2234,2235],{},"Calculer"," trois nouveaux nombres à partir de ",[805,2238,2172],{},[805,2240,2175],{},[805,2242,2179],{},[736,2244,2245,2248],{},[603,2246,2247],{},"Renvoyer"," ces trois nouveaux nombres : ce sera la nouvelle couleur du pixel.",[599,2250,2251,2252,2255],{},"Toute la créativité d'une retouche tient dans ",[603,2253,2254],{},"l'étape 2"," — la formule\nde calcul. Une formule = un effet. Voyons trois exemples au programme.",[594,2257,2259],{"id":2258},"exemple-1-le-négatif","Exemple 1 — Le négatif",[599,2261,2262,2263,2266],{},"L'effet ",[603,2264,2265],{},"négatif"," inverse l'intensité de chaque jauge : ce qui était à\nfond passe à zéro, ce qui était à zéro passe à fond. La formule est très\nsimple, et c'est la même pour les trois jauges :",[599,2268,2269],{},[898,2270,2272,2297],{"className":2271},[905],[898,2273,2275],{"className":2274},[909],[911,2276,2277],{"xmlns":913},[916,2278,2279,2294],{},[919,2280,2281,2284,2286,2288,2291],{},[922,2282,2283],{},"nouvelle valeur",[926,2285,928],{},[933,2287,2140],{},[926,2289,2290],{},"−",[922,2292,2293],{},"ancienne valeur",[940,2295,2296],{"encoding":942},"\\text{nouvelle valeur} = 255 - \\text{ancienne valeur}",[898,2298,2300,2321,2342],{"className":2299,"ariaHidden":948},[947],[898,2301,2303,2306,2312,2315,2318],{"className":2302},[952],[898,2304],{"className":2305,"style":957},[956],[898,2307,2309],{"className":2308},[961,962],[898,2310,2283],{"className":2311},[961],[898,2313],{"className":2314,"style":970},[969],[898,2316,928],{"className":2317},[974],[898,2319],{"className":2320,"style":970},[969],[898,2322,2324,2328,2331,2335,2339],{"className":2323},[952],[898,2325],{"className":2326,"style":2327},[956],"height:0.7278em;vertical-align:-0.0833em;",[898,2329,2140],{"className":2330},[961],[898,2332],{"className":2333,"style":2334},[969],"margin-right:0.2222em;",[898,2336,2290],{"className":2337},[2338],"mbin",[898,2340],{"className":2341,"style":2334},[969],[898,2343,2345,2348],{"className":2344},[952],[898,2346],{"className":2347,"style":957},[956],[898,2349,2351],{"className":2350},[961,962],[898,2352,2293],{"className":2353},[961],[599,2355,2356,2357,2360],{},"En Python, on écrit cette transformation comme une fonction qui prend les\ntrois nombres ",[805,2358,2359],{},"r, g, b"," et renvoie les trois nouveaux nombres :",[639,2362,2363],{},[599,2364,2365,2368,2369,2372,2373,2376,2377,2380,2381,620],{},[603,2366,2367],{},"Renvoyer plusieurs valeurs."," Une fonction Python peut renvoyer plusieurs\nvaleurs en les séparant par des virgules dans le ",[805,2370,2371],{},"return",". À l'appel, Python\nles regroupe en un ",[603,2374,2375],{},"trio"," affiché entre parenthèses, par exemple\n",[805,2378,2379],{},"(245, 55, 205)",". C'est une notation pratique pour un pixel ",[805,2382,2383],{},"(r, g, b)",[2385,2386,2387],"python-snippet",{},[1742,2388,2390],{"className":1744,"code":2389,"language":1746,"meta":726,"style":726},"def negatif(r, g, b):\n    return 255 - r, 255 - g, 255 - b\n\nprint(negatif(10, 200, 50))    # (245, 55, 205)\nprint(negatif(0, 0, 0))        # (255, 255, 255) — noir → blanc\nprint(negatif(255, 255, 255))  # (0, 0, 0)       — blanc → noir\n",[805,2391,2392,2404,2432,2436,2464,2486],{"__ignoreMap":726},[898,2393,2394,2397,2401],{"class":1751,"line":1204},[898,2395,2396],{"class":1754},"def",[898,2398,2400],{"class":2399},"snPdu"," negatif",[898,2402,2403],{"class":1765},"(r, g, b):\n",[898,2405,2406,2409,2412,2415,2418,2420,2422,2425,2427,2429],{"class":1751,"line":1181},[898,2407,2408],{"class":1754},"    return",[898,2410,2411],{"class":1758}," 255",[898,2413,2414],{"class":1754}," -",[898,2416,2417],{"class":1765}," r, ",[898,2419,2140],{"class":1758},[898,2421,2414],{"class":1754},[898,2423,2424],{"class":1765}," g, ",[898,2426,2140],{"class":1758},[898,2428,2414],{"class":1754},[898,2430,2431],{"class":1765}," b\n",[898,2433,2434],{"class":1751,"line":1784},[898,2435,1787],{"emptyLinePlaceholder":1194},[898,2437,2438,2441,2444,2447,2449,2452,2454,2457,2460],{"class":1751,"line":1790},[898,2439,2440],{"class":1758},"print",[898,2442,2443],{"class":1765},"(negatif(",[898,2445,2446],{"class":1758},"10",[898,2448,610],{"class":1765},[898,2450,2451],{"class":1758},"200",[898,2453,610],{"class":1765},[898,2455,2456],{"class":1758},"50",[898,2458,2459],{"class":1765},"))    ",[898,2461,2463],{"class":2462},"sCsY4","# (245, 55, 205)\n",[898,2465,2466,2468,2470,2472,2474,2476,2478,2480,2483],{"class":1751,"line":1808},[898,2467,2440],{"class":1758},[898,2469,2443],{"class":1765},[898,2471,2136],{"class":1758},[898,2473,610],{"class":1765},[898,2475,2136],{"class":1758},[898,2477,610],{"class":1765},[898,2479,2136],{"class":1758},[898,2481,2482],{"class":1765},"))        ",[898,2484,2485],{"class":2462},"# (255, 255, 255) — noir → blanc\n",[898,2487,2488,2490,2492,2494,2496,2498,2500,2502,2505],{"class":1751,"line":1819},[898,2489,2440],{"class":1758},[898,2491,2443],{"class":1765},[898,2493,2140],{"class":1758},[898,2495,610],{"class":1765},[898,2497,2140],{"class":1758},[898,2499,610],{"class":1765},[898,2501,2140],{"class":1758},[898,2503,2504],{"class":1765},"))  ",[898,2506,2507],{"class":2462},"# (0, 0, 0)       — blanc → noir\n",[772,2509,2510,2513],{},[599,2511,2512],{},"Lecture du code, ligne par ligne :",[733,2514,2515,2535,2545],{},[736,2516,2517,2520,2521,2524,2525,2528,2529,610,2531,610,2533,620],{},[805,2518,2519],{},"def negatif(r, g, b):"," — on ",[603,2522,2523],{},"définit"," une fonction ",[805,2526,2527],{},"negatif"," qui\nattend trois nombres ",[805,2530,2172],{},[805,2532,2175],{},[805,2534,2179],{},[736,2536,2537,2540,2541,2544],{},[805,2538,2539],{},"return 255 - r, 255 - g, 255 - b"," — la fonction ",[603,2542,2543],{},"renvoie"," les trois\nnouvelles valeurs, dans l'ordre rouge, vert, bleu.",[736,2546,2547,2520,2550,2553,2554,620],{},[805,2548,2549],{},"print(negatif(10, 200, 50))",[603,2551,2552],{},"appelle"," la fonction avec un pixel\nrougeâtre. Python répond ",[805,2555,2379],{},[594,2557,2559],{"id":2558},"exemple-2-les-niveaux-de-gris","Exemple 2 — Les niveaux de gris",[599,2561,2562,2563,2566,2567,2570],{},"Pour obtenir une ",[603,2564,2565],{},"nuance de gris",", les trois jauges doivent être\n",[603,2568,2569],{},"réglées sur la même valeur",". Plus la valeur est basse, plus le gris\nest sombre ; plus elle est haute, plus il est clair.",[599,2572,2573,2574,2577],{},"Quelle valeur commune choisir ? La plus simple est la ",[603,2575,2576],{},"moyenne"," des\ntrois composantes du pixel d'origine :",[599,2579,2580],{},[898,2581,2583,2619],{"className":2582},[905],[898,2584,2586],{"className":2585},[909],[911,2587,2588],{"xmlns":913},[916,2589,2590,2616],{},[919,2591,2592,2595,2597],{},[922,2593,2594],{},"moy",[926,2596,928],{},[2598,2599,2600,2614],"mfrac",{},[919,2601,2602,2605,2608,2610,2612],{},[2603,2604,2172],"mi",{},[926,2606,2607],{},"+",[2603,2609,2175],{},[926,2611,2607],{},[2603,2613,2179],{},[933,2615,720],{},[940,2617,2618],{"encoding":942},"\\text{moy} = \\frac{r + g + b}{3}",[898,2620,2622,2644],{"className":2621,"ariaHidden":948},[947],[898,2623,2625,2629,2635,2638,2641],{"className":2624},[952],[898,2626],{"className":2627,"style":2628},[956],"height:0.625em;vertical-align:-0.1944em;",[898,2630,2632],{"className":2631},[961,962],[898,2633,2594],{"className":2634},[961],[898,2636],{"className":2637,"style":970},[969],[898,2639,928],{"className":2640},[974],[898,2642],{"className":2643,"style":970},[969],[898,2645,2647,2651],{"className":2646},[952],[898,2648],{"className":2649,"style":2650},[956],"height:1.2772em;vertical-align:-0.345em;",[898,2652,2654,2659,2744],{"className":2653},[961],[898,2655],{"className":2656},[2657,2658],"mopen","nulldelimiter",[898,2660,2662],{"className":2661},[2598],[898,2663,2666,2735],{"className":2664},[998,2665],"vlist-t2",[898,2667,2669,2730],{"className":2668},[1002],[898,2670,2673,2689,2700],{"className":2671,"style":2672},[1006],"height:0.9322em;",[898,2674,2676,2680],{"style":2675},"top:-2.655em;",[898,2677],{"className":2678,"style":2679},[1013],"height:3em;",[898,2681,2683],{"className":2682},[1018,1019,1020,1021],[898,2684,2686],{"className":2685},[961,1021],[898,2687,720],{"className":2688},[961,1021],[898,2690,2692,2695],{"style":2691},"top:-3.23em;",[898,2693],{"className":2694,"style":2679},[1013],[898,2696],{"className":2697,"style":2699},[2698],"frac-line","border-bottom-width:0.04em;",[898,2701,2703,2706],{"style":2702},"top:-3.4461em;",[898,2704],{"className":2705,"style":2679},[1013],[898,2707,2709],{"className":2708},[1018,1019,1020,1021],[898,2710,2712,2717,2720,2724,2727],{"className":2711},[961,1021],[898,2713,2172],{"className":2714,"style":2716},[961,2715,1021],"mathnormal","margin-right:0.0278em;",[898,2718,2607],{"className":2719},[2338,1021],[898,2721,2175],{"className":2722,"style":2723},[961,2715,1021],"margin-right:0.0359em;",[898,2725,2607],{"className":2726},[2338,1021],[898,2728,2179],{"className":2729},[961,2715,1021],[898,2731,2734],{"className":2732},[2733],"vlist-s","​",[898,2736,2738],{"className":2737},[1002],[898,2739,2742],{"className":2740,"style":2741},[1006],"height:0.345em;",[898,2743],{},[898,2745],{"className":2746},[2747,2658],"mclose",[599,2749,2750,2751,620],{},"Le pixel transformé devient ",[805,2752,2753],{},"(moy, moy, moy)",[2385,2755,2756],{},[1742,2757,2759],{"className":1744,"code":2758,"language":1746,"meta":726,"style":726},"def gris(r, g, b):\n    moy = (r + g + b) \u002F\u002F 3   # \u002F\u002F = division entière\n    return moy, moy, moy\n\nprint(gris(255, 0, 0))      # (85, 85, 85)    — rouge devient gris moyen\nprint(gris(100, 100, 100))  # (100, 100, 100) — déjà gris, inchangé\nprint(gris(200, 50, 80))    # (110, 110, 110)\n",[805,2760,2761,2770,2802,2809,2813,2836,2858],{"__ignoreMap":726},[898,2762,2763,2765,2768],{"class":1751,"line":1204},[898,2764,2396],{"class":1754},[898,2766,2767],{"class":2399}," gris",[898,2769,2403],{"class":1765},[898,2771,2772,2775,2777,2780,2782,2785,2787,2790,2793,2796,2799],{"class":1751,"line":1181},[898,2773,2774],{"class":1765},"    moy ",[898,2776,928],{"class":1754},[898,2778,2779],{"class":1765}," (r ",[898,2781,2607],{"class":1754},[898,2783,2784],{"class":1765}," g ",[898,2786,2607],{"class":1754},[898,2788,2789],{"class":1765}," b) ",[898,2791,2792],{"class":1754},"\u002F\u002F",[898,2794,2795],{"class":1758}," 3",[898,2797,2798],{"class":2462},"   #",[898,2800,2801],{"class":2462}," \u002F\u002F = division entière\n",[898,2803,2804,2806],{"class":1751,"line":1784},[898,2805,2408],{"class":1754},[898,2807,2808],{"class":1765}," moy, moy, moy\n",[898,2810,2811],{"class":1751,"line":1790},[898,2812,1787],{"emptyLinePlaceholder":1194},[898,2814,2815,2817,2820,2822,2824,2826,2828,2830,2833],{"class":1751,"line":1808},[898,2816,2440],{"class":1758},[898,2818,2819],{"class":1765},"(gris(",[898,2821,2140],{"class":1758},[898,2823,610],{"class":1765},[898,2825,2136],{"class":1758},[898,2827,610],{"class":1765},[898,2829,2136],{"class":1758},[898,2831,2832],{"class":1765},"))      ",[898,2834,2835],{"class":2462},"# (85, 85, 85)    — rouge devient gris moyen\n",[898,2837,2838,2840,2842,2845,2847,2849,2851,2853,2855],{"class":1751,"line":1819},[898,2839,2440],{"class":1758},[898,2841,2819],{"class":1765},[898,2843,2844],{"class":1758},"100",[898,2846,610],{"class":1765},[898,2848,2844],{"class":1758},[898,2850,610],{"class":1765},[898,2852,2844],{"class":1758},[898,2854,2504],{"class":1765},[898,2856,2857],{"class":2462},"# (100, 100, 100) — déjà gris, inchangé\n",[898,2859,2860,2862,2864,2866,2868,2870,2872,2875,2877],{"class":1751,"line":1824},[898,2861,2440],{"class":1758},[898,2863,2819],{"class":1765},[898,2865,2451],{"class":1758},[898,2867,610],{"class":1765},[898,2869,2456],{"class":1758},[898,2871,610],{"class":1765},[898,2873,2874],{"class":1758},"80",[898,2876,2459],{"class":1765},[898,2878,2879],{"class":2462},"# (110, 110, 110)\n",[639,2881,2882,2896,2916],{},[599,2883,2884,2885,2887,2888,2891,2892,2895],{},"On utilise ",[805,2886,2792],{}," (deux barres obliques) pour la ",[603,2889,2890],{},"division entière"," : on\nveut un nombre entier entre 0 et 255, pas un nombre à virgule. La\ndifférence avec ",[805,2893,2894],{},"\u002F"," (une seule barre, division classique) :",[733,2897,2898,2908],{},[736,2899,2900,2903,2904,2907],{},[805,2901,2902],{},"7 \u002F 3"," vaut ",[805,2905,2906],{},"2.333…"," (un nombre à virgule),",[736,2909,2910,2903,2913,2915],{},[805,2911,2912],{},"7 \u002F\u002F 3",[805,2914,935],{}," (on garde uniquement la partie entière).",[599,2917,2918,2919,2921],{},"Comme une jauge RGB ne peut être qu'un entier de 0 à 255, c'est ",[805,2920,2792],{}," qu'il\nnous faut ici.",[772,2923,2924],{},[599,2925,2926],{},"La moyenne arithmétique est l'approche la plus simple. Des formules plus\nfidèles à la perception humaine pondèrent davantage le vert (notre œil y\nest plus sensible). À ce niveau, la version simple suffit.",[594,2928,2930],{"id":2929},"exemple-3-garder-uniquement-le-rouge","Exemple 3 — Garder uniquement le rouge",[599,2932,2933,2934,2937,2938,2940,2941,2943,2944,2946],{},"Un troisième effet classique : ",[603,2935,2936],{},"filtrer une couche"," en éteignant deux\ndes trois jauges. Pour ne garder que le rouge, on remet ",[805,2939,2175],{}," et ",[805,2942,2179],{}," à zéro\net on laisse ",[805,2945,2172],{}," tel quel.",[2385,2948,2949],{},[1742,2950,2952],{"className":1744,"code":2951,"language":1746,"meta":726,"style":726},"def filtre_rouge(r, g, b):\n    return r, 0, 0\n\nprint(filtre_rouge(200, 150, 50))   # (200, 0, 0)\nprint(filtre_rouge(100, 100, 100))  # (100, 0, 0)\n",[805,2953,2954,2963,2976,2980,3004],{"__ignoreMap":726},[898,2955,2956,2958,2961],{"class":1751,"line":1204},[898,2957,2396],{"class":1754},[898,2959,2960],{"class":2399}," filtre_rouge",[898,2962,2403],{"class":1765},[898,2964,2965,2967,2969,2971,2973],{"class":1751,"line":1181},[898,2966,2408],{"class":1754},[898,2968,2417],{"class":1765},[898,2970,2136],{"class":1758},[898,2972,610],{"class":1765},[898,2974,2975],{"class":1758},"0\n",[898,2977,2978],{"class":1751,"line":1784},[898,2979,1787],{"emptyLinePlaceholder":1194},[898,2981,2982,2984,2987,2989,2991,2994,2996,2998,3001],{"class":1751,"line":1790},[898,2983,2440],{"class":1758},[898,2985,2986],{"class":1765},"(filtre_rouge(",[898,2988,2451],{"class":1758},[898,2990,610],{"class":1765},[898,2992,2993],{"class":1758},"150",[898,2995,610],{"class":1765},[898,2997,2456],{"class":1758},[898,2999,3000],{"class":1765},"))   ",[898,3002,3003],{"class":2462},"# (200, 0, 0)\n",[898,3005,3006,3008,3010,3012,3014,3016,3018,3020,3022],{"class":1751,"line":1808},[898,3007,2440],{"class":1758},[898,3009,2986],{"class":1765},[898,3011,2844],{"class":1758},[898,3013,610],{"class":1765},[898,3015,2844],{"class":1758},[898,3017,610],{"class":1765},[898,3019,2844],{"class":1758},[898,3021,2504],{"class":1765},[898,3023,3024],{"class":2462},"# (100, 0, 0)\n",[599,3026,3027],{},"Sur une image entière, l'effet ressemble à une « lampe rouge » qui ne\nlaisse passer que cette couleur — un peu comme la lumière rouge d'un\nlaboratoire de photographie argentique.",[599,3029,3030,3031,3034,3035,3037,3038,3041,3042,3034,3045,3037,3047,770],{},"Par symétrie, on obtient un ",[603,3032,3033],{},"filtre vert"," en gardant seulement ",[805,3036,2175],{},"\n(formule ",[805,3039,3040],{},"(0, g, 0)",") et un ",[603,3043,3044],{},"filtre bleu",[805,3046,2179],{},[805,3048,3049],{},"(0, 0, b)",[594,3051,1419],{"id":1418},[718,3053,3056,3061],{"correct":852,"explanation":3054,"slug":3055},"Le négatif inverse l'intensité : 0 devient 255 (et inversement). La formule est `255 - ancien` pour chaque composante.","traitement-rgb-c2",[724,3057,3058],{"v-slot:question":726},[599,3059,3060],{},"Quelle opération transforme une composante en sa version « négatif » ?",[724,3062,3063],{"v-slot:choices":726},[733,3064,3065,3068,3071,3074],{},[736,3066,3067],{},"nouveau = 255 + ancien",[736,3069,3070],{},"nouveau = 255 - ancien",[736,3072,3073],{},"nouveau = ancien \u002F 255",[736,3075,3076],{},"nouveau = -ancien",[718,3078,3081,3086],{"correct":852,"explanation":3079,"slug":3080},"Un gris pur a r = g = b. Selon la valeur commune, c'est un gris plus ou moins clair (0 = noir, 255 = blanc).","traitement-rgb-c3",[724,3082,3083],{"v-slot:question":726},[599,3084,3085],{},"Dans un pixel en niveau de gris, les trois composantes RGB sont :",[724,3087,3088],{"v-slot:choices":726},[733,3089,3090,3093,3096],{},[736,3091,3092],{},"toutes nulles",[736,3094,3095],{},"toutes égales entre elles",[736,3097,3098],{},"toutes à 255",[718,3100,3103,3115],{"correct":2136,"explanation":3101,"slug":3102},"On garde la composante rouge `r = 120` et on remet vert et bleu à zéro.","traitement-rgb-c4",[724,3104,3105],{"v-slot:question":726},[599,3106,3107,3108,3111,3112,2193],{},"Quel pixel obtient-on en appliquant ",[805,3109,3110],{},"filtre_rouge"," à ",[805,3113,3114],{},"(120, 200, 80)",[724,3116,3117],{"v-slot:choices":726},[733,3118,3119,3122,3125,3128],{},[736,3120,3121],{},"(120, 0, 0)",[736,3123,3124],{},"(0, 200, 80)",[736,3126,3127],{},"(120, 200, 0)",[736,3129,3130],{},"(200, 0, 0)",[594,3132,3134],{"id":3133},"et-sur-une-image-entière","Et sur une image entière ?",[599,3136,3137,3138,3141,3142,3145,3146,3149],{},"Tout ce que vous venez d'écrire travaille sur ",[603,3139,3140],{},"un seul pixel",". Pour\nappliquer la transformation à une ",[603,3143,3144],{},"image complète",", le principe est\ntoujours le même : le programme ",[603,3147,3148],{},"parcourt toutes les cases de la grille","\net applique la fonction à chacune.",[1726,3151,3152,3168,3329],{"icon":1728,"title":1729},[599,3153,3154,3155,3157,3158,3160,3161,3167],{},"Le code ci-dessous (à observer, pas à reproduire) montre comment\nappliquer ",[805,3156,2527],{}," à toute une image avec la bibliothèque Python\n",[603,3159,1735],{},". Vous n'êtes pas censés savoir l'écrire : retenez\nseulement que ",[603,3162,3163,3164,3166],{},"la fonction ",[805,3165,2527],{}," reste exactement la même",", et que\nle reste sert juste à parcourir l'image et à enregistrer le résultat.",[1742,3169,3171],{"className":1744,"code":3170,"language":1746,"meta":726,"style":726},"from PIL import Image\n\ndef negatif(r, g, b):\n    return 255 - r, 255 - g, 255 - b\n\nsource = Image.open(\"photo.jpg\")\nlargeur, hauteur = source.size\nresultat = Image.new(\"RGB\", (largeur, hauteur))\n\nfor x in range(largeur):\n    for y in range(hauteur):\n        r, g, b = source.getpixel((x, y))\n        resultat.putpixel((x, y), negatif(r, g, b))\n\nresultat.save(\"negatif.jpg\")\n",[805,3172,3173,3183,3187,3195,3217,3221,3234,3244,3260,3264,3280,3296,3307,3313,3318],{"__ignoreMap":726},[898,3174,3175,3177,3179,3181],{"class":1751,"line":1204},[898,3176,1755],{"class":1754},[898,3178,1759],{"class":1758},[898,3180,1762],{"class":1754},[898,3182,1766],{"class":1765},[898,3184,3185],{"class":1751,"line":1181},[898,3186,1787],{"emptyLinePlaceholder":1194},[898,3188,3189,3191,3193],{"class":1751,"line":1784},[898,3190,2396],{"class":1754},[898,3192,2400],{"class":2399},[898,3194,2403],{"class":1765},[898,3196,3197,3199,3201,3203,3205,3207,3209,3211,3213,3215],{"class":1751,"line":1790},[898,3198,2408],{"class":1754},[898,3200,2411],{"class":1758},[898,3202,2414],{"class":1754},[898,3204,2417],{"class":1765},[898,3206,2140],{"class":1758},[898,3208,2414],{"class":1754},[898,3210,2424],{"class":1765},[898,3212,2140],{"class":1758},[898,3214,2414],{"class":1754},[898,3216,2431],{"class":1765},[898,3218,3219],{"class":1751,"line":1808},[898,3220,1787],{"emptyLinePlaceholder":1194},[898,3222,3223,3226,3228,3230,3232],{"class":1751,"line":1819},[898,3224,3225],{"class":1765},"source ",[898,3227,928],{"class":1754},[898,3229,1798],{"class":1765},[898,3231,1802],{"class":1801},[898,3233,1805],{"class":1765},[898,3235,3236,3239,3241],{"class":1751,"line":1824},[898,3237,3238],{"class":1765},"largeur, hauteur ",[898,3240,928],{"class":1754},[898,3242,3243],{"class":1765}," source.size\n",[898,3245,3246,3249,3251,3254,3257],{"class":1751,"line":1839},[898,3247,3248],{"class":1765},"resultat ",[898,3250,928],{"class":1754},[898,3252,3253],{"class":1765}," Image.new(",[898,3255,3256],{"class":1801},"\"RGB\"",[898,3258,3259],{"class":1765},", (largeur, hauteur))\n",[898,3261,3262],{"class":1751,"line":1853},[898,3263,1787],{"emptyLinePlaceholder":1194},[898,3265,3267,3269,3272,3274,3277],{"class":1751,"line":3266},10,[898,3268,1827],{"class":1754},[898,3270,3271],{"class":1765}," x ",[898,3273,1833],{"class":1754},[898,3275,3276],{"class":1758}," range",[898,3278,3279],{"class":1765},"(largeur):\n",[898,3281,3283,3286,3289,3291,3293],{"class":1751,"line":3282},11,[898,3284,3285],{"class":1754},"    for",[898,3287,3288],{"class":1765}," y ",[898,3290,1833],{"class":1754},[898,3292,3276],{"class":1758},[898,3294,3295],{"class":1765},"(hauteur):\n",[898,3297,3299,3302,3304],{"class":1751,"line":3298},12,[898,3300,3301],{"class":1765},"        r, g, b ",[898,3303,928],{"class":1754},[898,3305,3306],{"class":1765}," source.getpixel((x, y))\n",[898,3308,3310],{"class":1751,"line":3309},13,[898,3311,3312],{"class":1765},"        resultat.putpixel((x, y), negatif(r, g, b))\n",[898,3314,3316],{"class":1751,"line":3315},14,[898,3317,1787],{"emptyLinePlaceholder":1194},[898,3319,3321,3324,3327],{"class":1751,"line":3320},15,[898,3322,3323],{"class":1765},"resultat.save(",[898,3325,3326],{"class":1801},"\"negatif.jpg\"",[898,3328,1805],{"class":1765},[599,3330,3331,3332,3335],{},"L'idée à retenir : ",[603,3333,3334],{},"toute l'intelligence de la retouche tient dans la\nfonction qui transforme un pixel."," Le reste est de la mécanique de\nparcours.",[594,3337,1145],{"id":1144},[1147,3339,3340],{},[733,3341,3342,3348,3365],{},[736,3343,3344,3347],{},[603,3345,3346],{},"Toujours dans l'ordre R, G, B."," Le trio est dans cet ordre : rouge,\nvert, bleu. Pas dans un autre ordre.",[736,3349,3350,3356,3357,3360,3361,3364],{},[603,3351,3352,3353,620],{},"Les valeurs restent dans ",[805,3354,3355],{},"[0, 255]"," Si votre formule produit ",[805,3358,3359],{},"-5","\nou ",[805,3362,3363],{},"300",", c'est qu'elle est mal pensée — une jauge ne peut ni être\nnégative, ni dépasser le maximum.",[736,3366,3367,3373,3374,3376],{},[603,3368,3369,3370,3372],{},"Une fonction ",[805,3371,2527],{}," ne modifie pas le pixel d'origine"," : elle\n",[603,3375,2543],{}," un nouveau trio. Le pixel d'origine, lui, ne change pas.",[594,3378,1172],{"id":1171},[599,3380,3381,3382,3385],{},"Les effets que vous avez écrits sont les plus simples qui soient. On peut\nen imaginer beaucoup d'autres avec d'autres formules : éclaircir\n(ajouter à chaque composante), augmenter le contraste (étirer les\nvaleurs vers les extrêmes), virer en sépia (mélanger les composantes\nselon des coefficients fixes). Tous ces effets ne sont rien d'autre\nqu'",[603,3383,3384],{},"une formule différente sur les trois jauges",", appliquée à chaque\npixel de l'image.",[2067,3387,3388],{},"html pre.shiki code .s8jYJ, html code.shiki .s8jYJ{--shiki-light:#D73A49;--shiki-default:#D73A49;--shiki-dark:#F97583}html pre.shiki code .snPdu, html code.shiki .snPdu{--shiki-light:#6F42C1;--shiki-default:#6F42C1;--shiki-dark:#B392F0}html pre.shiki code .sxrX7, html code.shiki .sxrX7{--shiki-light:#24292E;--shiki-default:#24292E;--shiki-dark:#E1E4E8}html pre.shiki code .sBjJW, html code.shiki .sBjJW{--shiki-light:#005CC5;--shiki-default:#005CC5;--shiki-dark:#79B8FF}html pre.shiki code .sCsY4, html code.shiki .sCsY4{--shiki-light:#6A737D;--shiki-default:#6A737D;--shiki-dark:#6A737D}html .light .shiki span {color: var(--shiki-light);background: var(--shiki-light-bg);font-style: var(--shiki-light-font-style);font-weight: var(--shiki-light-font-weight);text-decoration: var(--shiki-light-text-decoration);}html.light .shiki span {color: var(--shiki-light);background: var(--shiki-light-bg);font-style: var(--shiki-light-font-style);font-weight: var(--shiki-light-font-weight);text-decoration: var(--shiki-light-text-decoration);}html .default .shiki span {color: var(--shiki-default);background: var(--shiki-default-bg);font-style: var(--shiki-default-font-style);font-weight: var(--shiki-default-font-weight);text-decoration: var(--shiki-default-text-decoration);}html .shiki span {color: var(--shiki-default);background: var(--shiki-default-bg);font-style: var(--shiki-default-font-style);font-weight: var(--shiki-default-font-weight);text-decoration: var(--shiki-default-text-decoration);}html .dark .shiki span {color: var(--shiki-dark);background: var(--shiki-dark-bg);font-style: var(--shiki-dark-font-style);font-weight: var(--shiki-dark-font-weight);text-decoration: var(--shiki-dark-text-decoration);}html.dark .shiki span {color: var(--shiki-dark);background: var(--shiki-dark-bg);font-style: var(--shiki-dark-font-style);font-weight: var(--shiki-dark-font-weight);text-decoration: var(--shiki-dark-text-decoration);}html pre.shiki code .sIIMD, html code.shiki .sIIMD{--shiki-light:#032F62;--shiki-default:#032F62;--shiki-dark:#9ECBFF}",{"title":726,"searchDepth":1181,"depth":1181,"links":3390},[3391,3392,3393,3394,3395,3396,3397,3398,3399,3400],{"id":596,"depth":1181,"text":597},{"id":2116,"depth":1181,"text":2117},{"id":2212,"depth":1181,"text":2213},{"id":2258,"depth":1181,"text":2259},{"id":2558,"depth":1181,"text":2559},{"id":2929,"depth":1181,"text":2930},{"id":1418,"depth":1181,"text":1419},{"id":3133,"depth":1181,"text":3134},{"id":1144,"depth":1181,"text":1145},{"id":1171,"depth":1181,"text":1172},"Modifier les composantes RGB d'un pixel pour obtenir négatif, gris ou filtre — un pixel à la fois.",{},[3404,3407,3409,3411],{"slug":2184,"kind":1197,"question":3405,"choices":3406,"correct":852,"multi":1199,"explanation":2183},"Que représente le pixel (0, 255, 0) ?",[2200,2203,2206,2209],{"slug":3055,"kind":1197,"question":3060,"choices":3408,"correct":852,"multi":1199,"explanation":3054},[3067,3070,3073,3076],{"slug":3080,"kind":1197,"question":3085,"choices":3410,"correct":852,"multi":1199,"explanation":3079},[3092,3095,3098],{"slug":3102,"kind":1197,"question":3412,"choices":3413,"correct":2136,"multi":1199,"explanation":3101},"Quel pixel obtient-on en appliquant filtre_rouge à (120, 200, 80) ?",[3121,3124,3127,3130],{"title":181,"description":3401},"An24ORL4aYCZt1l2Pcb9-4LJpPTAwmYfvxICMVSUf5U",{"id":3417,"title":163,"bo":1191,"body":3418,"description":3512,"eval":1191,"extension":1192,"labo":1191,"meta":3513,"navigation":1194,"path":164,"quizzes":3515,"readingTime":1204,"seo":3516,"stem":165,"tp":1191,"__hash__":3517},"cours\u002F0.snt-2nde\u002Fsg-photo-numerique\u002F0.index.md",{"type":591,"value":3419,"toc":3507},[3420,3424,3431,3454,3458,3479,3483],[594,3421,3423],{"id":3422},"au-programme","Au programme",[599,3425,3426,3427,3430],{},"Vous prenez une photo en moins d'une seconde. Pourtant, entre l'instant où vous\npressez le déclencheur et le moment où l'image s'affiche, des millions de\nmesures sont réalisées, puis des dizaines d'algorithmes interviennent pour\ntransformer ces mesures brutes en une image agréable à regarder. Ce chapitre\nvous propose d'",[603,3428,3429],{},"ouvrir la boîte noire"," de la photographie numérique.",[599,3432,3433,3434,3436,3437,3439,3440,3442,3443,3446,3447,3449,3450,3453],{},"Vous verrez d'abord ce qu'est un ",[603,3435,605],{}," photosensible, et la différence\nsouvent confondue entre ",[603,3438,636],{}," (les cellules du capteur) et ",[603,3441,761],{},"\n(les points de l'image). Vous découvrirez ensuite que la photographie moderne\nest largement ",[603,3444,3445],{},"calculée"," : autofocus, balance des blancs, HDR, débruitage —\nautant d'algorithmes qui interviennent avant même que l'image n'existe sous sa\nforme finale. Vous explorerez ensuite les ",[603,3448,1543],{},", ces informations\ncachées dans chaque fichier image, qui en disent parfois beaucoup plus que la\nphoto elle-même. Enfin, vous apprendrez à ",[603,3451,3452],{},"traiter une image par programme","\nen manipulant les trois composantes RGB d'un pixel.",[594,3455,3457],{"id":3456},"objectifs","Objectifs",[1726,3459,3462],{"icon":3460,"title":3461},"i-lucide-target","À la fin du chapitre, vous saurez",[733,3463,3464,3467,3470,3473,3476],{},[736,3465,3466],{},"Distinguer photosites et pixels, capteur et image, et estimer une résolution.",[736,3468,3469],{},"Calculer le nombre de couleurs représentables selon la profondeur de couleur.",[736,3471,3472],{},"Citer plusieurs algorithmes intervenant dans la fabrication d'une image numérique.",[736,3474,3475],{},"Lire et modifier les composantes RGB d'une image par un petit programme.",[736,3477,3478],{},"Identifier les métadonnées EXIF d'une photo et mesurer leurs enjeux de confidentialité.",[594,3480,3482],{"id":3481},"plan","Plan",[825,3484,3485,3491,3497,3502],{},[736,3486,3487,3490],{},[603,3488,3489],{},"Photosites, pixels, résolution"," — capteur, image, profondeur de couleur.",[736,3492,3493,3496],{},[603,3494,3495],{},"Les algorithmes des appareils photo"," — la photo, une image calculée.",[736,3498,3499,3501],{},[603,3500,177],{}," — l'envers du fichier image.",[736,3503,3504,3506],{},[603,3505,181],{}," — manipuler les trois composantes RGB.",{"title":726,"searchDepth":1181,"depth":1181,"links":3508},[3509,3510,3511],{"id":3422,"depth":1181,"text":3423},{"id":3456,"depth":1181,"text":3457},{"id":3481,"depth":1181,"text":3482},"Du capteur au fichier image, comprendre ce que voit — et calcule — un appareil photo numérique.",{"icon":3514},"i-lucide-camera",[],{"title":163,"description":3512},"b-WuflEFz7mKM-XfUzb8ivQ_BIJ3wwxsardPpbdIAxo",[3519,3897,4038,4216,4595],{"id":3520,"title":3521,"bo":3522,"body":3523,"description":3890,"eval":1191,"extension":1192,"labo":1191,"meta":3891,"navigation":1199,"path":3892,"quizzes":3893,"readingTime":1204,"seo":3894,"stem":3895,"tp":1191,"__hash__":3896},"coursMemo\u002F0.snt-2nde\u002Fsg-photo-numerique\u002F1.pixels-resolution.memo.md","Photosites, pixels et résolution — l'essentiel",[589],{"type":591,"value":3524,"toc":3883},[3525,3529,3542,3546,3686,3690,3826,3828,3848,3852],[594,3526,3528],{"id":3527},"en-une-phrase","En une phrase",[599,3530,781,3531,784,3533,3535,3536,3538,3539,3541],{},[603,3532,609],{},[603,3534,605],{}," ; un ",[603,3537,613],{}," est un\npoint coloré du ",[603,3540,757],{},". La résolution du capteur et celle de l'image\nne sont pas toujours identiques.",[594,3543,3545],{"id":3544},"à-mémoriser","À mémoriser",[733,3547,3548,3556,3565,3571,3577,3583,3677],{},[736,3549,3550,3553,3554,770],{},[603,3551,3552],{},"Capteur"," : grille de cellules sensibles à la lumière (les ",[603,3555,636],{},[736,3557,3558,3561,3562,620],{},[603,3559,3560],{},"Pixel"," : point de l'image finale, codé par 3 composantes ",[603,3563,3564],{},"RGB",[736,3566,3567,3570],{},[603,3568,3569],{},"Résolution capteur"," : nombre de photosites (souvent en Mpx).",[736,3572,3573,3576],{},[603,3574,3575],{},"Résolution image"," : largeur × hauteur, en pixels.",[736,3578,3579,3582],{},[603,3580,3581],{},"Profondeur de couleur"," : nombre de bits par composante.",[736,3584,3585,3586,620],{},"Formule : ",[898,3587,3589,3610],{"className":3588},[905],[898,3590,3592],{"className":3591},[909],[911,3593,3594],{"xmlns":913},[916,3595,3596,3608],{},[919,3597,3598,3600,3602],{},[922,3599,924],{},[926,3601,928],{},[930,3603,3604,3606],{},[933,3605,935],{},[922,3607,938],{},[940,3609,943],{"encoding":942},[898,3611,3613,3634],{"className":3612,"ariaHidden":948},[947],[898,3614,3616,3619,3625,3628,3631],{"className":3615},[952],[898,3617],{"className":3618,"style":957},[956],[898,3620,3622],{"className":3621},[961,962],[898,3623,924],{"className":3624},[961],[898,3626],{"className":3627,"style":970},[969],[898,3629,928],{"className":3630},[974],[898,3632],{"className":3633,"style":970},[969],[898,3635,3637,3641],{"className":3636},[952],[898,3638],{"className":3639,"style":3640},[956],"height:0.8491em;",[898,3642,3644,3647],{"className":3643},[961],[898,3645,935],{"className":3646},[961],[898,3648,3650],{"className":3649},[994],[898,3651,3653],{"className":3652},[998],[898,3654,3656],{"className":3655},[1002],[898,3657,3659],{"className":3658,"style":3640},[1006],[898,3660,3662,3665],{"style":3661},"top:-3.063em;margin-right:0.05em;",[898,3663],{"className":3664,"style":1014},[1013],[898,3666,3668],{"className":3667},[1018,1019,1020,1021],[898,3669,3671],{"className":3670},[961,1021],[898,3672,3674],{"className":3673},[961,962,1021],[898,3675,938],{"className":3676},[961,1021],[736,3678,3679,3680,3682,3683,3685],{},"Standard : ",[603,3681,1036],{}," → 256 niveaux × 3 = ",[603,3684,1108],{}," de couleurs.",[594,3687,3689],{"id":3688},"à-savoir-reconnaître","À savoir reconnaître",[659,3691,3692,3702],{},[662,3693,3694],{},[665,3695,3696,3699],{},[668,3697,3698],{},"Situation",[668,3700,3701],{},"Action à mener",[675,3703,3704,3715,3728,3819],{},[665,3705,3706,3709],{},[680,3707,3708],{},"« Mon appareil fait 48 Mpx »",[680,3710,3711,3712,3714],{},"C'est la résolution du ",[603,3713,605],{},", pas forcément celle des fichiers.",[665,3716,3717,3722],{},[680,3718,3719,3720],{},"Image en ",[805,3721,807],{},[680,3723,3724,3725,3727],{},"Calculer ",[805,3726,811],{}," → 12 Mpx.",[665,3729,3730,3733],{},[680,3731,3732],{},"Profondeur 4 bits",[680,3734,3735,3818],{},[898,3736,3738,3760],{"className":3737},[905],[898,3739,3741],{"className":3740},[909],[911,3742,3743],{"xmlns":913},[916,3744,3745,3757],{},[919,3746,3747,3753,3755],{},[930,3748,3749,3751],{},[933,3750,935],{},[933,3752,1135],{},[926,3754,928],{},[933,3756,1087],{},[940,3758,3759],{"encoding":942},"2^4 = 16",[898,3761,3763,3808],{"className":3762,"ariaHidden":948},[947],[898,3764,3766,3770,3799,3802,3805],{"className":3765},[952],[898,3767],{"className":3768,"style":3769},[956],"height:0.8141em;",[898,3771,3773,3776],{"className":3772},[961],[898,3774,935],{"className":3775},[961],[898,3777,3779],{"className":3778},[994],[898,3780,3782],{"className":3781},[998],[898,3783,3785],{"className":3784},[1002],[898,3786,3788],{"className":3787,"style":3769},[1006],[898,3789,3790,3793],{"style":3661},[898,3791],{"className":3792,"style":1014},[1013],[898,3794,3796],{"className":3795},[1018,1019,1020,1021],[898,3797,1135],{"className":3798},[961,1021],[898,3800],{"className":3801,"style":970},[969],[898,3803,928],{"className":3804},[974],[898,3806],{"className":3807,"style":970},[969],[898,3809,3811,3815],{"className":3810},[952],[898,3812],{"className":3813,"style":3814},[956],"height:0.6444em;",[898,3816,1087],{"className":3817},[961]," niveaux par composante.",[665,3820,3821,3823],{},[680,3822,1036],{},[680,3824,3825],{},"24 bits par pixel au total (3 × 8).",[594,3827,1145],{"id":1144},[733,3829,3830,3836,3842],{},[736,3831,3832,3835],{},[603,3833,3834],{},"Photosite ≠ pixel."," Pas synonymes : matériel vs informatique.",[736,3837,3838,3841],{},[603,3839,3840],{},"Plus de Mpx ≠ meilleure photo."," Photosites trop petits → bruit en basse lumière.",[736,3843,3844,3847],{},[603,3845,3846],{},"Profondeur ≠ résolution."," Deux notions indépendantes.",[594,3849,3851],{"id":3850},"ordres-de-grandeur","Ordres de grandeur",[659,3853,3854,3862],{},[662,3855,3856],{},[665,3857,3858,3860],{},[668,3859,1061],{},[668,3861,1067],{},[675,3863,3864,3870,3877],{},[665,3865,3866,3868],{},[680,3867,1074],{},[680,3869,1079],{},[665,3871,3872,3875],{},[680,3873,3874],{},"8 bits (standard)",[680,3876,1108],{},[665,3878,3879,3881],{},[680,3880,1113],{},[680,3882,1119],{},{"title":726,"searchDepth":1181,"depth":1181,"links":3884},[3885,3886,3887,3888,3889],{"id":3527,"depth":1181,"text":3528},{"id":3544,"depth":1181,"text":3545},{"id":3688,"depth":1181,"text":3689},{"id":1144,"depth":1181,"text":1145},{"id":3850,"depth":1181,"text":3851},"Mémo de révision sur la chaîne capteur → image et la profondeur de couleur.",{},"\u002Fsnt-2nde\u002Fsg-photo-numerique\u002Fpixels-resolution.memo",[],{"title":3521,"description":3890},"0.snt-2nde\u002Fsg-photo-numerique\u002F1.pixels-resolution.memo","7NA68Y26KTJXmIc5E0NF8RHUrtqBMZyVF2r4dYoRvp0",{"id":3898,"title":3899,"bo":3900,"body":3901,"description":4031,"eval":1191,"extension":1192,"labo":1191,"meta":4032,"navigation":1199,"path":4033,"quizzes":4034,"readingTime":1204,"seo":4035,"stem":4036,"tp":1191,"__hash__":4037},"coursMemo\u002F0.snt-2nde\u002Fsg-photo-numerique\u002F2.algorithmes-photo.memo.md","Les algorithmes de l'appareil photo — l'essentiel",[1210],{"type":591,"value":3902,"toc":4024},[3903,3905,3911,3913,3945,3947,3993,3995,4013,4017],[594,3904,3528],{"id":3527},[599,3906,3907,3908,3910],{},"Une photo numérique est ",[603,3909,3445],{}," : entre le capteur et le fichier, plusieurs\nalgorithmes interviennent pour décider de la netteté, des couleurs, de\nl'exposition et du bruit.",[594,3912,3545],{"id":3544},[733,3914,3915,3921,3927,3933,3939],{},[736,3916,3917,3920],{},[603,3918,3919],{},"Autofocus"," : choisit où placer la mise au point (contraste, phase, IA).",[736,3922,3923,3926],{},[603,3924,3925],{},"Balance des blancs"," : corrige la teinte globale selon la source lumineuse.",[736,3928,3929,3932],{},[603,3930,3931],{},"Exposition \u002F HDR"," : ajuste la quantité de lumière ; le HDR fusionne plusieurs prises.",[736,3934,3935,3938],{},[603,3936,3937],{},"Débruitage"," : lisse les pixels aléatoires en basse lumière.",[736,3940,3941,3944],{},[603,3942,3943],{},"Démosaïçage"," : reconstruit les 3 composantes RGB de chaque pixel à partir des photosites filtrés.",[594,3946,3689],{"id":3688},[659,3948,3949,3959],{},[662,3950,3951],{},[665,3952,3953,3956],{},[668,3954,3955],{},"Effet observé",[668,3957,3958],{},"Algorithme en cause",[675,3960,3961,3969,3977,3985],{},[665,3962,3963,3966],{},[680,3964,3965],{},"Image floue malgré l'autofocus",[680,3967,3968],{},"Pas assez de contraste (mur uni, basse lumière).",[665,3970,3971,3974],{},[680,3972,3973],{},"Photo « jaunâtre » sous une lampe",[680,3975,3976],{},"Balance des blancs mal calibrée.",[665,3978,3979,3982],{},[680,3980,3981],{},"Détails effacés sur une photo de nuit",[680,3983,3984],{},"Débruitage trop agressif.",[665,3986,3987,3990],{},[680,3988,3989],{},"Photo très contrastée d'un contre-jour",[680,3991,3992],{},"Mode HDR activé.",[594,3994,1145],{"id":1144},[733,3996,3997,4000,4010],{},[736,3998,3999],{},"Croire qu'une photo « sort du capteur » telle quelle — fausse impression.",[736,4001,4002,4003,4006,4007,4009],{},"Confondre ",[603,4004,4005],{},"netteté"," (mise au point) et ",[603,4008,1334],{}," (lumière).",[736,4011,4012],{},"Désactiver le HDR sans s'en rendre compte → contre-jours ratés.",[594,4014,4016],{"id":4015},"idée-clé","Idée-clé",[599,4018,4019,4020,4023],{},"La photo numérique est ",[603,4021,4022],{},"interprétée"," par l'appareil, bien avant d'être\nenregistrée. Connaître ces algorithmes vous aide à comprendre pourquoi deux\ntéléphones différents produisent deux photos différentes de la même scène.",{"title":726,"searchDepth":1181,"depth":1181,"links":4025},[4026,4027,4028,4029,4030],{"id":3527,"depth":1181,"text":3528},{"id":3544,"depth":1181,"text":3545},{"id":3688,"depth":1181,"text":3689},{"id":1144,"depth":1181,"text":1145},{"id":4015,"depth":1181,"text":4016},"Mémo de révision sur les algorithmes embarqués dans la prise de vue.",{},"\u002Fsnt-2nde\u002Fsg-photo-numerique\u002Falgorithmes-photo.memo",[],{"title":3899,"description":4031},"0.snt-2nde\u002Fsg-photo-numerique\u002F2.algorithmes-photo.memo","cVNKIkP4flaVR578zxDHd-xCJ2Ly4TrF--yxcE9t7tI",{"id":4039,"title":4040,"bo":4041,"body":4042,"description":4209,"eval":1191,"extension":1192,"labo":1191,"meta":4210,"navigation":1199,"path":4211,"quizzes":4212,"readingTime":1204,"seo":4213,"stem":4214,"tp":1191,"__hash__":4215},"coursMemo\u002F0.snt-2nde\u002Fsg-photo-numerique\u002F3.metadonnees-exif.memo.md","Les métadonnées EXIF — l'essentiel",[1511],{"type":591,"value":4043,"toc":4201},[4044,4046,4058,4060,4102,4104,4141,4145,4163,4165,4187,4191],[594,4045,3528],{"id":3527},[599,4047,1470,4048,4050,4051,4054,4055,620],{},[603,4049,1543],{}," sont les informations ",[603,4052,4053],{},"invisibles"," intégrées au\nfichier image : conditions de prise, appareil, lieu, date. Leur enjeu majeur\nest la ",[603,4056,4057],{},"confidentialité",[594,4059,3545],{"id":3544},[733,4061,4062,4071,4076],{},[736,4063,4064,4067,4068,620],{},[603,4065,4066],{},"EXIF"," = ",[846,4069,4070],{},"Exchangeable Image File Format",[736,4072,1561,4073,4075],{},[603,4074,1564],{}," = une donnée qui en décrit une autre.",[736,4077,4078,4079],{},"4 métadonnées emblématiques :\n",[733,4080,4081,4087,4092,4096],{},[736,4082,4083,4086],{},[603,4084,4085],{},"Date \u002F heure"," de la prise.",[736,4088,4089,4091],{},[603,4090,1642],{}," (les plus sensibles).",[736,4093,4094,620],{},[603,4095,1657],{},[736,4097,4098,4101],{},[603,4099,4100],{},"Réglages"," : ouverture, vitesse, ISO.",[594,4103,3689],{"id":3688},[659,4105,4106,4115],{},[662,4107,4108],{},[665,4109,4110,4112],{},[668,4111,3698],{},[668,4113,4114],{},"Bon réflexe",[675,4116,4117,4125,4133],{},[665,4118,4119,4122],{},[680,4120,4121],{},"Publier une photo de chez soi",[680,4123,4124],{},"Vérifier que les EXIF sont supprimées.",[665,4126,4127,4130],{},[680,4128,4129],{},"Photo reçue dont on doute de l'origine",[680,4131,4132],{},"Lire les EXIF — date, GPS, appareil.",[665,4134,4135,4138],{},[680,4136,4137],{},"Comprendre les choix techniques d'un photographe",[680,4139,4140],{},"Lire ses EXIF (ouverture, vitesse, ISO).",[594,4142,4144],{"id":4143},"outils-de-consultation","Outils de consultation",[733,4146,4147,4150,4156],{},[736,4148,4149],{},"Propriétés \u002F Détails (clic droit).",[736,4151,4152,4155],{},[1712,4153,1717],{"href":1714,"rel":4154},[1716]," en ligne.",[736,4157,4158,4159,4162],{},"Python : ",[805,4160,4161],{},"image.getexif()"," (PIL).",[594,4164,1145],{"id":1144},[733,4166,4167,4173,4180],{},[736,4168,4169,4172],{},[603,4170,4171],{},"Géolocalisation active par défaut"," sur la plupart des smartphones.",[736,4174,4175,4176,4179],{},"Croire qu'Instagram = pas d'EXIF partout. ",[603,4177,4178],{},"Vrai pour Instagram",",\npas pour les envois bruts (Discord, mail, hébergeurs d'images).",[736,4181,4182,4183,4186],{},"Oublier que ",[603,4184,4185],{},"tout fichier numérique"," contient des métadonnées : PDF,\naudio, vidéo.",[594,4188,4190],{"id":4189},"en-une-formule","En une formule",[599,4192,4193,4194,4197,4198,620],{},"Une photo n'est jamais ",[603,4195,4196],{},"juste"," une image — c'est toujours une image ",[603,4199,4200],{},"+ son\ncontexte numérique",{"title":726,"searchDepth":1181,"depth":1181,"links":4202},[4203,4204,4205,4206,4207,4208],{"id":3527,"depth":1181,"text":3528},{"id":3544,"depth":1181,"text":3545},{"id":3688,"depth":1181,"text":3689},{"id":4143,"depth":1181,"text":4144},{"id":1144,"depth":1181,"text":1145},{"id":4189,"depth":1181,"text":4190},"Mémo de révision sur les données cachées des fichiers image.",{},"\u002Fsnt-2nde\u002Fsg-photo-numerique\u002Fmetadonnees-exif.memo",[],{"title":4040,"description":4209},"0.snt-2nde\u002Fsg-photo-numerique\u002F3.metadonnees-exif.memo","JmTmX2e-tyoxjJ2d99Z3jhjDFDItjvIupyT03fGyfQE",{"id":4217,"title":4218,"bo":4219,"body":4220,"description":4588,"eval":1191,"extension":1192,"labo":1191,"meta":4589,"navigation":1199,"path":4590,"quizzes":4591,"readingTime":1204,"seo":4592,"stem":4593,"tp":1191,"__hash__":4594},"coursMemo\u002F0.snt-2nde\u002Fsg-photo-numerique\u002F4.traitement-rgb.memo.md","Traiter une image en Python — l'essentiel",[2093],{"type":591,"value":4221,"toc":4579},[4222,4224,4231,4235,4267,4271,4363,4367,4426,4491,4493,4543,4545,4567,4569,4576],[594,4223,3528],{"id":3527},[599,4225,4226,4227,4230],{},"Traiter une image, c'est ",[603,4228,4229],{},"modifier les trois composantes R, G, B"," de\nchaque pixel selon une formule. Tout l'effet d'une retouche tient dans\ncette formule, appliquée pixel par pixel.",[594,4232,4234],{"id":4233},"limage-mentale","L'image mentale",[733,4236,4237,4244,4251,4258],{},[736,4238,4239,4240,4243],{},"Une image = une ",[603,4241,4242],{},"grille de cases"," (les pixels).",[736,4245,4246,4247,4250],{},"Chaque case porte ",[603,4248,4249],{},"3 jauges"," : rouge, vert, bleu.",[736,4252,4253,4254,2137,4256,2141],{},"Chaque jauge va de ",[603,4255,2136],{},[603,4257,2140],{},[736,4259,4260,4261,610,4263,610,4265,620],{},"Un pixel = trois nombres, notés ",[805,4262,2172],{},[805,4264,2175],{},[805,4266,2179],{},[594,4268,4270],{"id":4269},"transformations-clés","Transformations clés",[659,4272,4273,4283],{},[662,4274,4275],{},[665,4276,4277,4280],{},[668,4278,4279],{},"Effet",[668,4281,4282],{},"Formule sur (r, g, b)",[675,4284,4285,4303,4318,4333,4348],{},[665,4286,4287,4292],{},[680,4288,4289],{},[603,4290,4291],{},"Négatif",[680,4293,4294,610,4297,610,4300],{},[805,4295,4296],{},"255 - r",[805,4298,4299],{},"255 - g",[805,4301,4302],{},"255 - b",[665,4304,4305,4310],{},[680,4306,4307],{},[603,4308,4309],{},"Niveau de gris",[680,4311,4312,4315,4316],{},[805,4313,4314],{},"moy = (r + g + b) \u002F\u002F 3"," puis ",[805,4317,2753],{},[665,4319,4320,4325],{},[680,4321,4322],{},[603,4323,4324],{},"Filtre rouge",[680,4326,4327,610,4329,610,4331],{},[805,4328,2172],{},[805,4330,2136],{},[805,4332,2136],{},[665,4334,4335,4340],{},[680,4336,4337],{},[603,4338,4339],{},"Filtre vert",[680,4341,4342,610,4344,610,4346],{},[805,4343,2136],{},[805,4345,2175],{},[805,4347,2136],{},[665,4349,4350,4355],{},[680,4351,4352],{},[603,4353,4354],{},"Filtre bleu",[680,4356,4357,610,4359,610,4361],{},[805,4358,2136],{},[805,4360,2136],{},[805,4362,2179],{},[594,4364,4366],{"id":4365},"syntaxe-python-par-pixel","Syntaxe Python (par pixel)",[1742,4368,4370],{"className":1744,"code":4369,"language":1746,"meta":726,"style":726},"def negatif(r, g, b):\n    return 255 - r, 255 - g, 255 - b\n\nprint(negatif(10, 200, 50))   # (245, 55, 205)\n",[805,4371,4372,4380,4402,4406],{"__ignoreMap":726},[898,4373,4374,4376,4378],{"class":1751,"line":1204},[898,4375,2396],{"class":1754},[898,4377,2400],{"class":2399},[898,4379,2403],{"class":1765},[898,4381,4382,4384,4386,4388,4390,4392,4394,4396,4398,4400],{"class":1751,"line":1181},[898,4383,2408],{"class":1754},[898,4385,2411],{"class":1758},[898,4387,2414],{"class":1754},[898,4389,2417],{"class":1765},[898,4391,2140],{"class":1758},[898,4393,2414],{"class":1754},[898,4395,2424],{"class":1765},[898,4397,2140],{"class":1758},[898,4399,2414],{"class":1754},[898,4401,2431],{"class":1765},[898,4403,4404],{"class":1751,"line":1784},[898,4405,1787],{"emptyLinePlaceholder":1194},[898,4407,4408,4410,4412,4414,4416,4418,4420,4422,4424],{"class":1751,"line":1790},[898,4409,2440],{"class":1758},[898,4411,2443],{"class":1765},[898,4413,2446],{"class":1758},[898,4415,610],{"class":1765},[898,4417,2451],{"class":1758},[898,4419,610],{"class":1765},[898,4421,2456],{"class":1758},[898,4423,3000],{"class":1765},[898,4425,2463],{"class":2462},[1742,4427,4429],{"className":1744,"code":4428,"language":1746,"meta":726,"style":726},"def gris(r, g, b):\n    moy = (r + g + b) \u002F\u002F 3\n    return moy, moy, moy\n\nprint(gris(255, 0, 0))        # (85, 85, 85)\n",[805,4430,4431,4439,4460,4466,4470],{"__ignoreMap":726},[898,4432,4433,4435,4437],{"class":1751,"line":1204},[898,4434,2396],{"class":1754},[898,4436,2767],{"class":2399},[898,4438,2403],{"class":1765},[898,4440,4441,4443,4445,4447,4449,4451,4453,4455,4457],{"class":1751,"line":1181},[898,4442,2774],{"class":1765},[898,4444,928],{"class":1754},[898,4446,2779],{"class":1765},[898,4448,2607],{"class":1754},[898,4450,2784],{"class":1765},[898,4452,2607],{"class":1754},[898,4454,2789],{"class":1765},[898,4456,2792],{"class":1754},[898,4458,4459],{"class":1758}," 3\n",[898,4461,4462,4464],{"class":1751,"line":1784},[898,4463,2408],{"class":1754},[898,4465,2808],{"class":1765},[898,4467,4468],{"class":1751,"line":1790},[898,4469,1787],{"emptyLinePlaceholder":1194},[898,4471,4472,4474,4476,4478,4480,4482,4484,4486,4488],{"class":1751,"line":1808},[898,4473,2440],{"class":1758},[898,4475,2819],{"class":1765},[898,4477,2140],{"class":1758},[898,4479,610],{"class":1765},[898,4481,2136],{"class":1758},[898,4483,610],{"class":1765},[898,4485,2136],{"class":1758},[898,4487,2482],{"class":1765},[898,4489,4490],{"class":2462},"# (85, 85, 85)\n",[594,4492,3689],{"id":3688},[659,4494,4495,4504],{},[662,4496,4497],{},[665,4498,4499,4501],{},[668,4500,3698],{},[668,4502,4503],{},"Action",[675,4505,4506,4514,4522,4532],{},[665,4507,4508,4511],{},[680,4509,4510],{},"Couleur (0, 0, 0)",[680,4512,4513],{},"Noir (toutes jauges éteintes).",[665,4515,4516,4519],{},[680,4517,4518],{},"Couleur (255, 255, 255)",[680,4520,4521],{},"Blanc (toutes jauges à fond).",[665,4523,4524,4529],{},[680,4525,4526],{},[805,4527,4528],{},"r = g = b",[680,4530,4531],{},"Une nuance de gris.",[665,4533,4534,4537],{},[680,4535,4536],{},"Effet identique sur toute l'image",[680,4538,1561,4539,4542],{},[603,4540,4541],{},"fonction"," appliquée à chaque pixel.",[594,4544,1145],{"id":1144},[733,4546,4547,4552,4561],{},[736,4548,4549,4550,620],{},"Confondre l'ordre des composantes : c'est toujours ",[603,4551,2359],{},[736,4553,4554,4555,4560],{},"Produire une valeur ",[603,4556,4557,4558],{},"hors de ",[805,4559,3355],{}," — c'est le signe que la\nformule est mal posée.",[736,4562,4563,4564,4566],{},"Croire que la fonction modifie le pixel d'origine : non, elle ",[603,4565,2543],{},"\nun nouveau trio.",[594,4568,4190],{"id":4189},[599,4570,4571,4572,4575],{},"Une retouche photo = ",[603,4573,4574],{},"une formule sur trois nombres",", appliquée à toutes\nles cases de la grille.",[2067,4577,4578],{},"html pre.shiki code .s8jYJ, html code.shiki .s8jYJ{--shiki-light:#D73A49;--shiki-default:#D73A49;--shiki-dark:#F97583}html pre.shiki code .snPdu, html code.shiki .snPdu{--shiki-light:#6F42C1;--shiki-default:#6F42C1;--shiki-dark:#B392F0}html pre.shiki code .sxrX7, html code.shiki .sxrX7{--shiki-light:#24292E;--shiki-default:#24292E;--shiki-dark:#E1E4E8}html pre.shiki code .sBjJW, html code.shiki .sBjJW{--shiki-light:#005CC5;--shiki-default:#005CC5;--shiki-dark:#79B8FF}html pre.shiki code .sCsY4, html code.shiki .sCsY4{--shiki-light:#6A737D;--shiki-default:#6A737D;--shiki-dark:#6A737D}html .light .shiki span {color: var(--shiki-light);background: var(--shiki-light-bg);font-style: var(--shiki-light-font-style);font-weight: var(--shiki-light-font-weight);text-decoration: var(--shiki-light-text-decoration);}html.light .shiki span {color: var(--shiki-light);background: var(--shiki-light-bg);font-style: var(--shiki-light-font-style);font-weight: var(--shiki-light-font-weight);text-decoration: var(--shiki-light-text-decoration);}html .default .shiki span {color: var(--shiki-default);background: var(--shiki-default-bg);font-style: var(--shiki-default-font-style);font-weight: var(--shiki-default-font-weight);text-decoration: var(--shiki-default-text-decoration);}html .shiki span {color: var(--shiki-default);background: var(--shiki-default-bg);font-style: var(--shiki-default-font-style);font-weight: var(--shiki-default-font-weight);text-decoration: var(--shiki-default-text-decoration);}html .dark .shiki span {color: var(--shiki-dark);background: var(--shiki-dark-bg);font-style: var(--shiki-dark-font-style);font-weight: var(--shiki-dark-font-weight);text-decoration: var(--shiki-dark-text-decoration);}html.dark .shiki span {color: var(--shiki-dark);background: var(--shiki-dark-bg);font-style: var(--shiki-dark-font-style);font-weight: var(--shiki-dark-font-weight);text-decoration: var(--shiki-dark-text-decoration);}",{"title":726,"searchDepth":1181,"depth":1181,"links":4580},[4581,4582,4583,4584,4585,4586,4587],{"id":3527,"depth":1181,"text":3528},{"id":4233,"depth":1181,"text":4234},{"id":4269,"depth":1181,"text":4270},{"id":4365,"depth":1181,"text":4366},{"id":3688,"depth":1181,"text":3689},{"id":1144,"depth":1181,"text":1145},{"id":4189,"depth":1181,"text":4190},"Mémo de référence pour transformer un pixel par programme.",{},"\u002Fsnt-2nde\u002Fsg-photo-numerique\u002Ftraitement-rgb.memo",[],{"title":4218,"description":4588},"0.snt-2nde\u002Fsg-photo-numerique\u002F4.traitement-rgb.memo","Nmrs1Zz3n1NgoQEc2ae0uUIhU-ljqK7qdjoeXh9i1wc",{"id":4596,"title":4597,"bo":4598,"body":4599,"description":4940,"eval":1191,"extension":1192,"labo":1191,"meta":4941,"navigation":1199,"path":4943,"quizzes":4944,"readingTime":1204,"seo":4965,"stem":4966,"tp":1191,"__hash__":4967},"coursMemo\u002F0.snt-2nde\u002Fsg-photo-numerique\u002Fchapitre.memo.md","Photographie numérique — synthèse",[1511,589,1210,2093],{"type":591,"value":4600,"toc":4935},[4601,4605,4611,4629,4655,4664,4689,4693,4766,4770,4794,4823,4845,4855,4864,4879,4907],[594,4602,4604],{"id":4603},"vue-densemble","Vue d'ensemble",[599,4606,4607,4608,4610],{},"Le chapitre s'est attaché à ",[603,4609,3429],{}," de la photographie\nnumérique. La trajectoire suivie repart du matériel pour aller vers les\nusages.",[599,4612,4613,4614,4616,4617,4619,4620,4622,4623,4625,4626,4628],{},"D'abord, le ",[603,4615,605],{}," : une grille de ",[603,4618,636],{}," qui mesurent chacun une\nintensité lumineuse à travers un filtre coloré. Cette première étape pose le\nvocabulaire — ",[603,4621,609],{}," (sur le capteur) et ",[603,4624,613],{}," (dans l'image) ne\nsont pas synonymes, et leurs résolutions peuvent différer. La ",[603,4627,619],{}," complète le tableau : avec 8 bits par composante, on dispose de 256\nniveaux par couleur, soit environ 16,7 millions de couleurs au total.",[599,4630,4631,4632,4635,4636,4638,4639,4641,4642,2940,4644,4646,4647,4649,4650,4652,4653,620],{},"Mais une photo ne sort jamais brute du capteur. Une chaîne d'",[603,4633,4634],{},"algorithmes","\nintervient en amont du fichier : ",[603,4637,1243],{}," pour la mise au point,\n",[603,4640,1307],{}," pour neutraliser la teinte de la lumière ambiante,\n",[603,4643,1334],{},[603,4645,1340],{}," pour gérer la dynamique lumineuse, ",[603,4648,1377],{},"\npour lisser les pixels aléatoires, ",[603,4651,1397],{}," pour reconstruire les trois\ncomposantes RGB de chaque pixel. La photo numérique est, en grande partie, une\nphoto ",[603,4654,3445],{},[599,4656,4657,4658,4660,4661,4663],{},"Une fois enregistré, le fichier image porte par ailleurs autre chose que ses\npixels : des ",[603,4659,1543],{}," — date, GPS, modèle d'appareil, réglages.\nInvisibles à l'œil, elles sont lisibles par tout logiciel adapté, et leur\ndiffusion non maîtrisée pose un enjeu de ",[603,4662,4057],{}," majeur.",[599,4665,4666,4667,4670,4671,4674,4675,4677,4678,4681,4682,4685,4686,4688],{},"Cette nature calculée se prolonge enfin ",[603,4668,4669],{},"côté logiciel"," : un programme peut\n",[603,4672,4673],{},"manipuler"," une image en agissant sur les composantes R, G, B de chaque\npixel. Vous avez appris à écrire en Python les fonctions du ",[603,4676,2265],{},", des\n",[603,4679,4680],{},"niveaux de gris",", et d'un ",[603,4683,4684],{},"filtre de couche"," — toutes au format\n« je reçois ",[805,4687,2359],{},", je renvoie un nouveau trio ». C'est exactement ce que\nfont les filtres des applications de retouche, à plus grande échelle.",[594,4690,4692],{"id":4691},"carte-des-notions","Carte des notions",[659,4694,4695,4708],{},[662,4696,4697],{},[665,4698,4699,4702,4705],{},[668,4700,4701],{},"Cours",[668,4703,4704],{},"Notion centrale",[668,4706,4707],{},"Items BO",[675,4709,4710,4724,4738,4752],{},[665,4711,4712,4717,4720],{},[680,4713,4714],{},[603,4715,4716],{},"1. Photosites, pixels et résolution",[680,4718,4719],{},"Capteur, image, profondeur de couleur.",[680,4721,4722],{},[805,4723,589],{},[665,4725,4726,4731,4734],{},[680,4727,4728],{},[603,4729,4730],{},"2. Les algorithmes de l'appareil photo",[680,4732,4733],{},"La photo est calculée (autofocus, BdB, HDR, débruitage, démosaïçage).",[680,4735,4736],{},[805,4737,1210],{},[665,4739,4740,4745,4748],{},[680,4741,4742],{},[603,4743,4744],{},"3. Les métadonnées EXIF",[680,4746,4747],{},"Données invisibles du fichier image, enjeux de confidentialité.",[680,4749,4750],{},[805,4751,1511],{},[665,4753,4754,4759,4762],{},[680,4755,4756],{},[603,4757,4758],{},"4. Traiter une image en Python",[680,4760,4761],{},"Manipuler les trois composantes RGB par programme, pixel par pixel.",[680,4763,4764],{},[805,4765,2093],{},[594,4767,4769],{"id":4768},"auto-évaluation","Auto-évaluation",[718,4771,4773,4778],{"correct":852,"slug":4772},"sg-photo-numerique-1-q1",[724,4774,4775],{"v-slot:question":726},[599,4776,4777],{},"Sur un capteur d'appareil photo numérique, comment s'appelle une cellule\nsensible à la lumière ?",[724,4779,4780],{"v-slot:choices":726},[733,4781,4782,4785,4788,4791],{},[736,4783,4784],{},"Un pixel",[736,4786,4787],{},"Un photosite",[736,4789,4790],{},"Un voxel",[736,4792,4793],{},"Un bit",[718,4795,4798,4807],{"correct":4796,"slug":4797},"0,1","sg-photo-numerique-1-q2",[724,4799,4800],{"v-slot:question":726},[599,4801,4802,4803,4806],{},"Lesquelles de ces affirmations sont ",[603,4804,4805],{},"vraies"," au sujet d'une image\nnumérique en mode RGB 8 bits ? (plusieurs réponses possibles)",[724,4808,4809],{"v-slot:choices":726},[733,4810,4811,4814,4817,4820],{},[736,4812,4813],{},"Chaque composante d'un pixel peut prendre 256 valeurs.",[736,4815,4816],{},"Un pixel peut représenter environ 16,7 millions de couleurs.",[736,4818,4819],{},"Chaque composante peut prendre 2 048 valeurs.",[736,4821,4822],{},"Une image n'a pas de profondeur de couleur.",[718,4824,4826,4831],{"correct":935,"slug":4825},"sg-photo-numerique-1-q3",[724,4827,4828],{"v-slot:question":726},[599,4829,4830],{},"Quel algorithme reconstruit les trois composantes RGB de chaque pixel à\npartir des photosites filtrés du capteur ?",[724,4832,4833],{"v-slot:choices":726},[733,4834,4835,4838,4840,4843],{},[736,4836,4837],{},"L'autofocus",[736,4839,1443],{},[736,4841,4842],{},"Le démosaïçage",[736,4844,1440],{},[4846,4847,4850],"self-eval-free-text",{"answer":4066,"slug":4848,"case-sensitive":4849},"sg-photo-numerique-1-q4","false",[724,4851,4852],{"v-slot:question":726},[599,4853,4854],{},"Quel est le nom (en quatre lettres) du format standard des métadonnées d'une\nphoto numérique ?",[4846,4856,4859],{"answer":1087,"slug":4857,"tolerance":2136,"type":4858},"sg-photo-numerique-1-q5","number",[724,4860,4861],{"v-slot:question":726},[599,4862,4863],{},"Avec une profondeur de couleur de 4 bits par composante, combien de niveaux\npeut-on coder pour chaque couleur ?",[4846,4865,4867],{"answer":2140,"slug":4866,"tolerance":2136,"type":4858},"sg-photo-numerique-1-q6",[724,4868,4869],{"v-slot:question":726},[599,4870,4871,4872,4874,4875,4878],{},"Pour calculer le négatif d'une composante de pixel valant ",[805,4873,2172],{}," (cas standard\n8 bits), la formule canonique s'écrit ",[805,4876,4877],{},"nouveau = X - r",". Quelle est la valeur\nde X ?",[4880,4881,4883,4888],"self-eval-ordering",{"slug":4882},"sg-photo-numerique-1-q7",[724,4884,4885],{"v-slot:question":726},[599,4886,4887],{},"Remettez dans l'ordre les étapes simplifiées d'une prise de vue numérique :",[724,4889,4890],{"v-slot:items":726},[733,4891,4892,4895,4898,4901,4904],{},[736,4893,4894],{},"Les photosites du capteur mesurent la lumière à travers leurs filtres colorés",[736,4896,4897],{},"L'algorithme de démosaïçage reconstruit les composantes RGB de chaque pixel",[736,4899,4900],{},"Les algorithmes de balance des blancs et de débruitage ajustent les couleurs",[736,4902,4903],{},"Les métadonnées EXIF sont écrites dans le fichier final",[736,4905,4906],{},"L'image est enregistrée sur le stockage de l'appareil",[718,4908,4910,4919],{"correct":852,"slug":4909},"sg-photo-numerique-1-q8",[724,4911,4912],{"v-slot:question":726},[599,4913,4914,4915,4918],{},"Quelle est la principale ",[603,4916,4917],{},"inquiétude de confidentialité"," liée aux\nmétadonnées EXIF ?",[724,4920,4921],{"v-slot:choices":726},[733,4922,4923,4926,4929,4932],{},[736,4924,4925],{},"L'ouverture utilisée révèle un savoir-faire technique",[736,4927,4928],{},"Les coordonnées GPS révèlent l'emplacement précis de la prise",[736,4930,4931],{},"Le modèle de l'appareil est une information sensible",[736,4933,4934],{},"La date est secrète",{"title":726,"searchDepth":1181,"depth":1181,"links":4936},[4937,4938,4939],{"id":4603,"depth":1181,"text":4604},{"id":4691,"depth":1181,"text":4692},{"id":4768,"depth":1181,"text":4769},"Vue d'ensemble du chapitre, points-clés et auto-évaluation finale.",{"self_eval_slug":4942},"snt-2nde-sg-photo-numerique","\u002Fsnt-2nde\u002Fsg-photo-numerique\u002Fchapitre.memo",[4945,4947,4950,4952,4956,4957,4959,4962],{"slug":4772,"kind":1197,"question":4777,"choices":4946,"correct":852,"multi":1199,"explanation":726},[4784,4787,4790,4793],{"slug":4797,"kind":1197,"question":4948,"choices":4949,"correct":4796,"multi":1194,"explanation":726},"Lesquelles de ces affirmations sont vraies au sujet d'une image\nnumérique en mode RGB 8 bits ? (plusieurs réponses possibles)",[4813,4816,4819,4822],{"slug":4825,"kind":1197,"question":4830,"choices":4951,"correct":935,"multi":1199,"explanation":726},[4837,1443,4842,1440],{"slug":4848,"kind":4953,"question":4854,"answer":4066,"caseSensitive":1199,"tolerance":4954,"inputType":4955,"explanation":726},"free_text",0,"string",{"slug":4857,"kind":4953,"question":4863,"answer":1087,"caseSensitive":1199,"tolerance":4954,"inputType":4858,"explanation":726},{"slug":4866,"kind":4953,"question":4958,"answer":2140,"caseSensitive":1199,"tolerance":4954,"inputType":4858,"explanation":726},"Pour calculer le négatif d'une composante de pixel valant r (cas standard\n8 bits), la formule canonique s'écrit nouveau = X - r. Quelle est la valeur\nde X ?",{"slug":4882,"kind":4960,"question":4887,"items":4961,"explanation":726},"ordering",[4894,4897,4900,4903,4906],{"slug":4909,"kind":1197,"question":4963,"choices":4964,"correct":852,"multi":1199,"explanation":726},"Quelle est la principale inquiétude de confidentialité liée aux\nmétadonnées EXIF ?",[4925,4928,4931,4934],{"title":4597,"description":4940},"0.snt-2nde\u002Fsg-photo-numerique\u002Fchapitre.memo","GHAQ7xnihJYxkbEYp3toGK0F8-G5Edr9GTGJWwX4wLA",1788035577195]