title: Estimating illuminant color based on luminance balance of surfaces.
abstract: To accomplish color constancy the illuminant color needs to be discounted from the light reflected from surfaces. Some strategies for discounting the illuminant color use statistics of luminance and chromaticity distribution in natural scenes. In this study we showed whether color constancy exploits the potential cue that was provided by the luminance balance of differently colored surfaces. In our experiments we used six colors: bright and dim red, green, and blue, as surrounding stimulus colors. In most cases, bright colors were set to be optimal colors. They were arranged among 60 hexagonal elements in close-packed structure. The center element served as the test stimulus. The observer adjusted the chromaticity of the test stimulus to obtain a perceptually achromatic surface. We used simulated black body radiations of 3000 (or 4000), 6500, and 20000 K as test illuminants. The results showed that the luminance balance of surfaces with no chromaticity shift had clear effects on the observer's achromatic setting, which was consistent with our hypothesis on estimating the scene illuminant based on optimal colors.
authors.affiliation: Department of Information Processing, Tokyo Institute of Technology, 226-8502 Yokohama, Japan. uchikawa@ip.titech.ac.jp
authors.forename: Keiji
authors.initials: K
authors.lastname: Uchikawa
authors.forename: Kazuho
authors.initials: K
authors.lastname: Fukuda
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Kitazawa
authors.forename: Donald I A
authors.initials: DI
authors.lastname: MacLeod
mesh_terms: D055984:Cathode Ray Tube; D003116:Color; D003118:Color Perception / Q000502:physiology*; D003463:Cues; D006801:Humans; D010775:Photic Stimulation; D013499:Surface Properties