PSYB57H3 Chapter Notes - Chapter 2: Binocular Disparity, Random Dot Stereogram, Depth Perception
Document Summary
Humans see range on electromagnetic spectrum from 400nm to 700nm. Color is not a physical characteristic but a product of the physical stimulus interacting with na nervous system. 3 cone photoreceptors w/different photo pigment (different sensitivity to light of different wavelengths). S-cones (short-wavelength cones peak at 420nm), m-cones (medium- wavelength cones peak at 535, l-cones (long-wavelength cones peak at 565nm). Cones work at daylight levels (photopic), rod works in dimmer light levels (scotopic). Problem of univariance: a cone can only provide single type of information (neural firing rate), where as we need it to correspond to 2 types of information, being amplitude and wavelength corresponding to color and brightness. Problem of univariance is reason for lack of color in dimly lit scenes, making it impossible to discriminate colors under scotopic conditions. Trichromatic solution: differences between wavelengths or mixtures of wavelengths are detectable due to different types of cones (s, m, l). Metamers: mixtures of different wavelengths that look identical. (1.
