Highlighting illumination color by three-dimensional perception of scene moderates color constancy decline by systematic surface color change in stimulus background.

In our previous work [J. Opt. Soc. Am. A42, B81 (2025)JOAOD60740-323210.1364/JOSAA.545278], we demonstrated that the spatial local contrast influences color constancy performance by combining the effects of illuminant colors and background surface colors in two-dimensional (2D) stimuli. In this study, we investigated the impact of perceived scene dimensionality, achieved by using the perspective space technique in which a lighting box filled with a chromatic illuminant was simulated (abbreviated as 2D+ scene) on color constancy. White daylight (D65) and red, green, blue, and yellow chromatic illuminants illuminated the reference and test stimuli in a haploscopic view, respectively. Each stimulus consisted of a central 1.2° test patch surrounded by a 4.2° background of Mondrian-like overlapping chromatic patches and an outer 0.4° gray fringe. On a neutral background, the colors of the patches were in the hue circle around gray, and on chromatic backgrounds dominated by red, green, blue, and yellow, these patch colors were systematically shifted to one color direction in maintaining the hue circle. In the first two conditions, both the reference and test stimuli had the same background (neutral and complementary to the illuminant color). In contrast, in the last two conditions, in which both the illuminant color and the background dominant colors were systematically controlled, the reference and test stimuli had different backgrounds, and the color appearance of the backgrounds, except at the fringe, looked similar (the color of the illuminant and neutral). The results showed that in the 2D scene, the color constancy remarkably declined with systematic surface color changes under the last two conditions. On the contrary, in the 2D+ scene, this decline was strongly moderated, although the decline was still statistically significant, except for the green illuminant. These results suggest that if the illuminant color is perceived as a 3D light source in the 2D+ scene, the effectiveness of the illumination estimation is recovered, and the local contrast mechanism still partially contributes to color constancy. However, the simultaneous and systematic color shifts in illuminants and background surfaces still reduced the color constancy performance, despite the lighting box and fringe providing clear and consistent cues to estimate the illuminant colors.