Quantifying color constancy: evidence for nonlinear processing of cone-specific contrast
article
Color constancy was studied by the method of comparing color samples under two different illuminants using a CRT color monitor. In addition to the classical approach in which one of the illuminants is a (standard) white, we performed experiments in which the range of differential illumination was extended by using pairs of lights that were both colored. The stimulus pattern consisted of an array of thirty-five color samples (including five neutral samples) on a white background. A trichromatic illuminant-object interaction was simulated analogous to that resulting from illumination by three mono-chromatic lights. The test samples, as seen under "test" and "match" illumina-tion, were successively presented to the left and right eye (haploscopic matching). The data show systematic deviations from predictions on the basis of cone-specific normalization procedures like those incorporated in the Retinex algorithm and the von Kries transformation. The results can be described by a nonlinear response transformation that depends on two factors, receptor-specific sample/background contrast and the extent to which the illuminant stimulates the receptor system in question. The latter factor explains the deviations. These are mainly caused by the short-wave-sensitive system, as a consequence of the fact that this system can be more selectively stimulated than the other, spectrally less separated, cone systems.
Topics
Color constancyColor visionCone-specific contrastNonlinear responseTrichromatic reflectancereceptorcolorcomparative studycontrastexperimental testhuman experimentilluminationnonlinear systemnormal humannormal valuepredictionpriority journalretina conesamplestimulustissue specificityvisual display unitColor PerceptionHumanLightMathematicsModels, PsychologicalPhotoreceptorsSupport, Non-U.S. Gov't
TNO Identifier
7728
Source title
Vision Research
Pages
739-757
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