Color constancy via chromaticity neutralization: From single to multiple illuminants

In this paper, an improved color constancy approach is presented by considering the disadvantage of the well-known max-RGB algorithm: Only the unreliable maximum intensities are taken for illuminant estimation. To solve this problem, we propose the chromaticity neutralization process, which selects the representative pixels for robust illuminant computing. Moreover, to deal with the color deviation cases under multiple illuminant sources, we further present a procedure by first softly clustering the image pixels into several groups; the estimated illuminants from these groups are then combined based on the clustering weights to specifically determine the illuminant of each pixel. The experiments on two databases and web images demonstrate the effectiveness of our approach.