Color image enhancement algorithm based on improved Retinex algorithm

In order to solve the problem of low expressiveness caused by color distortion and poor saturation when performing image enhancement with classic Retinex algorithm, this paper proposes a color image enhancement algorithm base on the improved Retinex algorithm. In this algorithm, the input image is decomposed into illumination component and reflection component base on Retinex theory first, then logarithmic transformation and Gaussian filtering are performed on the illumination component of HSV color space to approximate the visual system's perception intensity to physical reflectance. Next, the estimated illumination value of scene is used to adjust the multi-scale reflection components of the input image, and to obtain a preliminarily enhanced image. Finally, a color correction factor is introduced into the initial enhanced image to obtain the final enhanced image base on gray world hypothesis. Experimental results show that compared with several classical Retinex algorithms, the proposed algorithm can effectively improve the brightness, contrast and visual information fidelity of the input image without color distortion.