Color image enhancement based on single-scale retinex with a JND-based nonlinear filter

In this paper, we propose a color image enhancement based on the single-scale retinex (SSR) with a just noticeable difference (JND)-based nonlinear filter. In the proposed method, an input RGB color image is transformed into an HSV color image, Under the assumption of white-light illumination, the S and V component images are enhanced In the enhancement of the V component image, the illumination is first estimated using the JND-based nonlinear filter. The output V component image is then obtained by subtracting some portion of the log signal of the estimated illumination from the log signal of the input V component image. The histogram modeling is next applied to the output V component image. The S component image is enhanced in proportion to the enhanced ratio of the V component image. Finally an output RGB color image is obtained from the enhanced V and S component images along with the original H component image. Experimental results show that the proposed method yields better performance of color enhancement over the conventional histogram equalization and SSR for test color images.