title: Scene articulation: dependence of illuminant estimates on number of surfaces.
abstract: The ability of observers to detect changes in illuminant over two scenes containing different random samples of reflecting surfaces was determined in an experiment with Mondrian-like patterns containing different numbers of coloured patches. Performance was found to improve as the number of patches increased from 9 to 49. In principle, observers could have used space-average scene colour as the cue ('grey-world' hypothesis) or the colour of the brightest surface in the scene ('bright-is-white' hypothesis), as the two cues generally covary. In a second experiment, observers matched illuminants across different patterns in which the space-average cue and the brightest-patch cue were independently manipulated. The articulation of the patterns was varied: the number of patches increased from 49 (patch width 1 deg visual angle) to over 50000 (patch width 0.03 deg), while the gamut of colours was held constant. Space-average colour was found to be the dominant cue with all patterns except for those with the largest patches.
authors.affiliation: Behavioural Brain Sciences, School of Psychology, University of Birmingham, UK. k.j.linnell@bham.ac.uk
authors.forename: Karina J
authors.initials: KJ
authors.lastname: Linnell
authors.forename: David H
authors.initials: DH
authors.lastname: Foster
mesh_terms: D003118:Color Perception / Q000502:physiology*; D003196:Computer Graphics; D003463:Cues; D006801:Humans; D010775:Photic Stimulation; D011581:Psychological Tests; D013028:Space Perception / Q000502:physiology*