Abstract

Theoretical work on color constancy has dwelt on the problem of estimating surface and illuminant chromatic properties in the case where a set of surfaces is viewed under a single illuminant^1-5. Maloney and Wandell⁴ used linear models to describe variation among surface reflectance functions^6-9 and variation among illuminants^10,11 to establish a general result for this situation: a trichromatic system viewing surfaces under a single unknown illuminant that is represented by three color descriptors can recover two color- constant descriptors per surface. Their remarkable result is incomplete, however. First, it is desirable to recover three or more descriptors per surface, for neither surface color percepts¹² nor surface color properties^6-9 are described adequately by two-dimensional models. Second, one would prefer the recovery of surface reflectance descriptors to be independent of the choice of a particular model of illumination. The model that describes accurately the daylight illumination environment^10,11, for instance, will generally fail to describe other illumination environments such as those found indoors or that presented by the red, green and blue lights used in Land's demonstrations with Mondrians¹.

© 1992 Optical Society of America