Perceptual distortion analysis of color image VQ-based coding

It is generally accepted that a RGB color image can be easily encoded by using a gray-scale compression technique on each of the three color planes. Such an approach, however, fails to take into account correlations existing between color planes and perceptual factors. We evaluated several linear and non linear color spaces, some introduced by the CIE (Commission Internationale de l'Eclairage), compressed with the Vector Quantization (VQ) technique for minimum perceptual distortion. To study these distortions, we measured contrast and luminance of the video framebuffer, to precisely control color. We then obtained psychophysical judgments to measure hom well these methods work to minimize perceptual distortion in a variety of color space.