Abstract

The luminance pattern presented to the eye is the product of separate patterns of illumination and object reflectance. In many situations, the viewer is at least moderately successful in factoring this product into its components and separately perceiving the pattern of illumination and the pattern of object reflectance. Approximate lightness constancy is one aspect of this ability. One necessary condition is that illumination and reflectance have different spatial distributions, and this fact suggests that size-tuned mechanisms may play an important role. The nature of any such role is complicated by the fact that, in the space domain, the illumination and reflectance patterns are multiplied. Consequently, in the frequency domain, where the selectivities of tuned mechanisms are most conveniently defined, the spectra of the illumination and reflectance patterns are convolved with one another.

© 1987 Optical Society of America