From [R,G,B] to surface reflectance: computing color constant descriptors in images

Abstract

This paper addresses the issue of color constancy, which is the the perceptual ability of the human visual system to assign the same colors to objects under different lighting conditions. We propose a method, based on finite-dimensional linear models of reflectance and illumination, which allows the transformation [R,G,B] images into color constant images. In contrast to previous work, we show that good results can be obtained using a 3-receptor system and some knowledge about the spectral properties of natural materials and illuminants. In the method developed, an estimate of illuminant in the scene is computed, which allows the computation of color constant descriptors of the pixel values in the image. In addition, we show a method of computing the actual reflectances of the materials in the scene out of the computed color descriptors.