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Cônes et bâtonnets. Sensibilité spectrale des photorécepteurs.

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Presentation on theme: "Cônes et bâtonnets. Sensibilité spectrale des photorécepteurs."— Presentation transcript:

1 Cônes et bâtonnets

2 Sensibilité spectrale des photorécepteurs

3 Mélange soustractif des couleurs (pigments)

4 Mélange additif des couleurs (lumières)

5 Color matching

6 Trichromacy

7 Trichromacy (Young-Helmholtz) 3 primaires = blanc X = A + B+ C Télévision, imprimerie

8 Munsell system

9 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 ( t and ), microspectrometry from Brown and Wald ( n and ) and increment threshold producing artificial monochromasy from Brinley ( and s ) and increment threshold measurements from Wald ( 5 ) (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)

10 Champs de sensibilité aux couleurs

11 Table 1 Prevalence of congenital colour deficiencies Types of colour vision deficiencymalesfemales Overall~8%~0.5% Anomalous trichromacy protanomaly1%0.01% Deutanomaly5%0.4% tritanomalyrarerare Dichromacy protanopia1%0.01% Deuteranopia1.5%0.01% tritanopia*0.008%0.008% Monochromacy rod monochromacyrarerare cone monochromacyrarerare atypical monochromacyv. rarev. rare Modified after Cole (1972), Pease (1998) and estimates from Wright (1952)*

12 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

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15 Hue cancellation (Jameson & Hurvich) monochromatique ajouter V ou R pour paraître ni V ni R

16 Codage des couleurs

17 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 ( t and ), microspectrometry from Brown and Wald ( n and ) and increment threshold producing artificial monochromasy from Brinley ( and s ) and increment threshold measurements from Wald ( 5 ) (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)

18 Décorrelation

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25 Modèle bilinéaire de la constance des couleurs Maloney & Wandell, 1986

26 Approximation de 6 réflectivités 3 fonctions de base 2 fonctions de base 1 fonction de base

27 Fonctions de base de réflectivité

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30 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.


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