Image enhancement based on Retinex and lightness decomposition

In this paper, an efficient image enhancement method based on Retinex and lightness decomposition is proposed, which enhances details and preserves the naturalness simultaneously. The quality of an enhanced image is determined by two factors, details and naturalness. Accordingly, the lightness is proposed to be decomposed into reflex lightness and ambience illumination. The reflex lightness is utilized to extract details based on Retinex, and the ambience illumination is utilized to maintain the naturalness of scenes. Moreover, a coarse evaluation that keeps the corresponding order of ambience illumination is proposed to substitute the absolute amount of ambience illumination, which may not be necessary to preserve the naturalness. The experimental results demonstrate that the proposed method can efficiently improve the perceptual quality of images by not only enhancing the details of the images, but also keeping the naturalness of scenes.