Contrast Enhancement with Chromaticity Error Bound

All existing contrast enhancement methods focus on heightening of spatial details in the luminance channel, with no or little consideration of the color fidelity of the processed images; they can introduce highly noticeable distortions in hue and saturation. This long-time much overlooked problem is addressed by this paper. A new algorithm based on Wu's optimal contrast-tone mapping (OCTM) is proposed to make maximal gain of contrast while keeping the hue component the same and at the same time respecting an upper bound on the distortion of saturation. Experimental results demonstrate the superior perceptual quality of the new chromaticity-conserving contrast enhancement algorithm over existing methods.