An Opponent Process Approach to Modeling the Blue Shift of the Human Color Vision System
- Brian Barsky
- Todd Kosloff
- Steven D. Upstill
Low light level affects human visual perception in various ways. Visual acuity is reduced and scenes appear bluer, darker, less saturated, and with reduced contrast. We confine our attention to an approach to modeling the appearance of the bluish cast in dim light, which is known as blue shift. Both photographs and computer-generated images of night scenes can be made to appear more realistic by understanding these phenomena as well as how they are produced by the retina. The retina comprises two kinds of photoreceptors, called rods and cones. The rods are more sensitive in dim light than are the cones. Although there are three different kinds of cones with different spectral sensitivity curves, all rods have the same spectral response curve. Consequently, rods provide luminance information but no color discrimination. Thus, when the light is too dim to fully excite the cones, scenes appear desaturated. The opponent process theory of color vision [Hurvich and Jameson 1957] states that the outputs of the rods and cones are encoded as red-green, yellow-blue, and white-black opponent channels. We model loss of saturation and blue shift in this opponent color space.
Brian A. Barsky, Todd J. Kosloff, , and Steven D. Upstill. "An Opponent Process Approach to Modeling the Blue Shift of the Human Color Vision System". In Applied Perception in Graphics and Visualization, 2004.