A Retinex algorithm for night color image enhancement by MRF

As Retinex algorithm usually has the problems of halo artifacts,color distortion,high noises and poor details in a low-illumination night color image,this paper proposes a novel Retinex enhancement algorithm based on Markov Random Fields(MRF)to enhance the visibility of single image. This algorithm uses the linear guided filter to estimate image illumination component in HSV(Hue Saturation Value)color space.The reflection image can be obtained through MRF model,and the night color image can be enhanced after color restoration and brightness correction.Compared with the original images,the experimental results demonstrate that the mean value(luminance)of image restored by proposed method has increased more than 2times,and the evaluation indexes such as standard deviation,entropy,the Peak Signal and Noise Ratio(PSNR)and so on have increased more than 5%.Compared with other Retinex algorithms,the effect of enhancement of this algorithm is more remarkable in halo effect elimination,noise suppression and detail preservation.