Abstract
Specular highlight on object surfaces is a candidate cue for color constancy, because in many cases it directly reflects spectral components of illuminants in the scene. Previous studies reported small effects of specular highlight on color constancy for human observers. In this study, we further investigated effects of specular highlight on color constancy in the black background, which suppresses strong effects of background color adjacent to a target object. In our psychophysical experiment, the stimulus was composed of a test object at the center of an LCD monitor and its surrounding objects, which gave observers illumination cues, on a black background. The luminances and chromaticities of the surrounding objects were set so that their surfaces with spectral reflectance of Munsell color chips was illuminated by D65, A, or 25000K illuminant. In addition, we had two conditions about glossiness of the surrounding objects: Gloss (with specular highlight) and Mat (without specular highlight) conditions. The observer conducted two kinds of tasks for the stimulus. One task was appearance achromatic setting, in which the observer adjusted the chromaticity of the test object so that its appearance became achromatic. The other was paper achromatic setting, in which the observer adjusted the test chromaticity so that its appearance matched a gray object illuminated by the scene illuminant. The results of appearance setting demonstrated slight improvement of color constancy for the Gloss condition than the Mat condition, as expected from the previous studies. In addition, the effect of gloss was much larger for the paper setting than the appearance setting. These results support the previous studies in that effects of specular highlight on color appearance shift due to color constancy are small, and suggest its much stronger effects on recognition of scene illuminant
Meeting abstract presented at VSS 2016