Illumination Estimation Based on Color Invariant

Illumination estimation is most important step in color constancy computation. Although a number of elaborate algorithms were proposed, methods like grey world and Max_RGB are still widely used because of their low computational costs. The grey world algorithm is based on the grey world assumption: the average reflectance in a scene is achromatic. But this assumption can not be always satisfied well. Borrowing on some of the strengths and simplicity of the grey world algorithm, we propose a novel algorithm called Illumination estimation based on color invariant (IECI) to improve the performance of grey world, in which the achromatic surfaces are identified for illumination estimation. As we know, the color of achromatic surface can completely reflect the illumination color incident on the scene. In light of this idea, color invariant technique is introduced to approximately identify the achromatic surfaces, then iterative method is used to improve accuracy of the proposed method. The experimental results show that the proposed algorithm can get satisfying results and outperforms some current state-of-the-art color constancy algorithms.