Color image enhancement method based on convex combination coefficients transformation using CIELAB color space

The HSV color space is generally used for color image enhancement. However, since the HSV color space does not take into account human visual perception, it fails to adequately represent perceived differences in brightness, making it less effective for contrast enhancement. In this paper, we propose a method for color image enhancement using the CIELAB color space, which is one of the uniform color spaces that quantitatively represent the differences in colors perceived by humans. Each pixel in the CIELAB color space is represented by a convex combination of four colors, white, black, bright pure color, and dark pure color. The image brightness contrast and colorfulness are enhanced by transforming the coefficients so that their distribution approximates the target histograms, each of which is derived from a uniform distribution in the CIELAB color space.