Abstract: In order to solve the problem of haze phenomenon and image detail expression in single-scale Retinex image enhancement algorithm due to lack of light, a color image enhancement algorithm based on improved single-scale Retinex algorithm is proposed. Firstly, the weighted least square method is used to enhance the details of the original color image. Secondly, 
optimization  of the original image is carried out. The gain coefficient is constructed for the processed image layer and the detail image layer, and a new merged image is reconstructed and output. The experimental results show that the proposed algorithm can effectively remove the haze phenomenon, make the details and contract of the image more prominent, and enhance the brightness. Compared with other traditioanl algorithms, the objective eva- luation index of image processing has been greatly improved, and the image enhancement ability has been significantly improved.

Key words: image enhancement, Retinex algorithm, least square method, image reconstruction