| Maloney, L.T. Color Vision: From Genes to Perception 1999 [pdf] |
| Surface Color Perception. The study of surface color perception is a proper subset of the study of color perception, and one way to highlight the difference between them is to consider the effective stimulus appropriate to each. The effective stimulus for the study of color perception, broadly construed, is the spectral power distribution of light arriving at each point of the left and right retinas. There is no assumption that the patterns of light correspond to any possible arrangement of surfaces, objects and illuminants in a three-dimensional scene. In contrast, the study of surface color perception presupposes that the light reaching the retinas has a history. The effective stimulus is the result of the interaction of certain light sources (the illuminant) with the surfaces of objects in an environment. It is clear that any stimulus appropriate for the study of surface color perception is also appropriate for the study of color perception but not vice versa. |
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| Maloney, L.T. Illuminant cues in surface color perception: tests of three candidate cues Vision Research 2001 (41):2581-2600 [pdf] |
| Many recent computational models of surface color perception presuppose information about illumination in scenes. The models differ primarily in the physical process each makes use of as a cue to the illuminant. We evaluated whether the human visual system makes use of any of three of the following candidate illuminant cues: (1) specular highlight, (2) full surface specularity [Lee, H. C. (1986). Method for computing the scene-illuminant chromaticity from specular highlights. Journal of the Optical Society of America A, 3(10), 1694 1699; D Zmura, M., & Lennie, P. (1986). Mechanisms of color constancy. Journal of the Optical Society of America A, 3(10), 1662 1672], and (3) uniform background. Observers viewed simulated scenes binocularly in a computer-controlled Wheatstone stereoscope. All simulated scenes contained a uniform background plane perpendicular to the observer s line of sight and a small number of specular, colored spheres resting on the uniform background. Scenes were rendered under either standard illuminant D65 or standard illuminant A. Observers adjusted the color of a small, simulated test patch to appear achromatic. In a series of experiments we perturbed the illuminant color signaled by each candidate cue and looked for an influence of the changed cue on achromatic settings. We found that the specular highlight cue had a significant influence, but that the influence was asymmetric: greater when the base illuminant, CIE standard Illuminant A, was perturbed in the direction of Illuminant D65 than vice versa. Neither the full surface specularity cue nor the background cue had any observable influence. The lack of influence of the background cue is likely due to the placement of the test patch in front of the background rather than, as is typical, embedded in the background |
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| Maloney, L.T. Illuminant estimation as cue combination Journal of Vision 2002 (2):493-504 [pdf] |
| This work briefly describes a model for illuminant estimation based on combination of candidate illuminant cues. Many of the research issues concerning cue combination in depth and shape perception translate well to the study of surface color perception. I describe and illustrate a particular experimental approach (perturbation analysis) employed in the study of depth and shape that is useful in determining whether hypothetical illuminant cues are actually used in color vision. |
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