Color fidelity of chromatic distributions by triad illuminant comparison

Performance measures for quantifying human color constancy and computational color constancy are very different. The former relate to measurements on individual object colors whereas the latter relate to the accuracy of the estimated illuminant. To bridge this gap, we propose a psychophysical method in which observers judge the global color fidelity of the visual scene rendered under different illuminants. In each experimental trial, the scene is rendered under three illuminants, two chromatic test illuminants and one neutral reference illuminant. Observers indicate which of the two test illuminants leads to better color fidelity in comparison to the reference illuminant. Here we study multicolor scenes with chromatic distributions that are differently oriented in color space, while having the same average chromaticity. We show that when these distributions are rendered under colored illumination they lead to different perceptual estimates of the color fidelity.