title: Colour constancy under simultaneous changes in surface position and illuminant.
abstract: Two kinds of constancy underlie the everyday perception of surface colour: constancy under changes in illuminant and constancy under changes in surface position. Classically, these two constancies seem to place conflicting demands on the visual system: to both take into account the region surrounding a surface and also discount it. It is shown here, however, that the ability of observers to make surface-colour matches across simultaneous changes in test-surface position and illuminant in computer-generated 'Mondrian' patterns is almost as good as across changes in illuminant alone. Performance was no poorer when the surfaces surrounding the test surface were permuted, or when information from a potential comparison surface, the one with the highest luminance, was suppressed. Computer simulations of cone-photoreceptor activity showed that a reliable cue for making surface-colour matches in all experimental conditions was provided by the ratios of cone excitations between the test surfaces and a spatial average over the whole pattern.
authors.affiliation: Visual and Computational Neuroscience Group, University of Manchester Institute of Science and Technology, Manchester M60 1QD, UK.
authors.forename: Kinjiro
authors.initials: K
authors.lastname: Amano
authors.forename: David H
authors.initials: DH
authors.lastname: Foster
mesh_terms: D000328:Adult; D003116:Color; D003118:Color Perception / Q000502:physiology*; D003198:Computer Simulation; D005260:Female; D006801:Humans; D008029:Lighting; D008297:Male; D010775:Photic Stimulation; D017949:Retinal Cone Photoreceptor Cells / Q000502:physiology; D013499:Surface Properties