<title>Use of a model of the human visual system to determine the attributes of aperture colors: hue, brightness, and saturation</title>

Abstract

A previously developed model of the human fovea is modified for analysis of colored stimuli. Psychophysical data on perception of aperture colors are used as a guide for the development of color perception by the model. The channels carrying information about color are represented by the summed responses of midget C- and L-type cells. The spectral energy distribution of any colored stimulus produces within the cell types a unique pattern of activities from which the amounts of each of the hues, whiteness, brightness, and saturation can be determined. The present analysis is restricted to the blue-cone region of the parafovea, which surrounds the blue-cone-free central fovea. For aberration-free dispersion and for no or little self-adaptation, the psychophysical and model data are in good agreement as to the 3 attributes hue, brightness, and saturation. As a result of univariance, information as to the spectral distribution of the stimulus cannot be used, and this creates a problem as how to normalize colored stimuli to a common set of standards. A method based on normalization of the outputs of the retinal cells to a common white is presented.