Computational approaches to color constancy: adaptive and ontogenetic considerations

Recent computational approaches to color constancy can be realized using a two-stage model of color vision. Adaptation at both the sensor stage and the second or reflectance channel stage is necessary to compute illuminant-invariant reflectance estimates. von Kries adaptation is shown to contribute significantly toward reducing, but not completely eliminating, the need for adaptation at the second stage. Examples of computations from the model using daylight illuminants, simulated natural reflectance functions, and putative human spectral sensitivity functions are shown. The ontogenetic plausibility of these models is also discussed. The role of the second-stage transformation in estimating surface reflectance is compared with the role of opponent color transformations in decorrelating primary receptor outputs.