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Cônes et bâtonnets
Sensibilité spectrale des photorécepteurs
Mélange soustractif des couleurs (pigments)
Mélange additif des couleurs (lumières)
Color matching
Trichromacy
Trichromacy (Young-Helmholtz)
• 3 primaires = blanc
• X = A + B+ C
• Télévision, imprimerie
Munsell system
Sensibilité spectrale des cônes
Figure 1. Spectral sensitivity of the S-cone, M-cone and L-cone. Combined results from various authors using different methods including retinal densitometry from Rushton ( and ), microspectrometry from Brown and Wald ( and “ ) and increment threshold producing artificial monochromasy from Brinley ( and ) and increment threshold measurements from Wald ( ) (From Moses, R. A. and Hart, W. M. (Ed) Adler's Physiology of the Eye, Clinical Application. St. Louis: The C. V. Mosby Company, 1987.(12 K jpeg image)
Champs de sensibilité aux couleurs
Table 1 Prevalence of congenital colour deficiencies
Types of colour visiondeficiency males femalesOverall ~8% ~0.5%Anomalous trichromacy protanomaly 1% 0.01%Deutanomaly 5% 0.4%tritanomaly rare rareDichromacy protanopia 1% 0.01%Deuteranopia 1.5% 0.01%tritanopia* 0.008% 0.008%Monochromacy rod monochromacy rare rarecone monochromacy rare rareatypical monochromacy v. rare v. rare
Modified after Cole (1972), Pease (1998) and estimates from Wright (1952)*
Opponency (Hering)
• Post-images
• Noms des couleurs 4: R V J B
• Pas de teintes RV, JB
• Lumière blanche = R + V = J + B
• Jameson & Hurvich hue cancellation
Hue cancellation (Jameson &
Hurvich)
monochromatique
ajouter V ou Rpour paraître ni V ni R
Codage des couleurs
Sensibilité spectrale des cônes
Figure 1. Spectral sensitivity of the S-cone, M-cone and L-cone. Combined results from various authors using different methods including retinal densitometry from Rushton ( and ), microspectrometry from Brown and Wald ( and “ ) and increment threshold producing artificial monochromasy from Brinley ( and ) and increment threshold measurements from Wald ( ) (From Moses, R. A. and Hart, W. M. (Ed) Adler's Physiology of the Eye, Clinical Application. St. Louis: The C. V. Mosby Company, 1987.(12 K jpeg image)
Décorrelation
Modèle bilinéairede la constancedes couleurs
Maloney &Wandell, 1986
Approximation de 6 réflectivités
3 fonctionsde base
2 fonctionsde base
1 fonctionde base
Fonctions de base de réflectivité
Sommation spatiale et temporelle
THE LAWS OF SPATIAL and TEMPORAL SUMMATION
Spatial Summation: RICCO'S LAW the detectability of a near-threshold flash of light depends only on the product (photons per unit area) X (flash area). Holds only for spots up to 1 degree across at most (in rod vision), and only for very very tiny spots in foveal vision. (NOTE: error in text book) Temporal Summation: BLOCH's LAW the detectability of a near-threshold flash of light depends only on the product (photons/ unit time) X (flash duration). Holds up to 0.2 sec inrod vision, but only up to around 0.05 sec in cone vision.