Retinex Image Enhancement Algorithm Based on Rotational Symmetric Bilateral Filtering

Abstract

Aiming at the shortage that single scale Retinex algorithm has the halo phenomenon,noise amplification phenomenon and image graying,based on rotational symmetric bilateral filtering,this paper proposes a Retinex image enhancement algorithm.The illumination images are estimated with bilateral filtering invariant to rotation and their influence on visual effect is removed to get the reflecting images’ attributes,which can overcome the halo phenomenon effectively.Then threshold values are determined by Otsu threshold segmentation algorithm to judge the bright areas and dark areas of images,and the noise in these areas is removed to varying degrees by bilateral filtering,which can remove noise as well as reserve image details.The contrast in low contrast regions is enhanced with piecewise linear transformation,which can improve the insufficient about grey phenomenon of images.Experimental results show that the proposed algorithm can remove the halo phenomenon effectively,improve the noise amplification phenomenon significantly,get more abundant image information and enhance the contrast of images,which is better than the single scale Retinex algorithm and the Retinex algorithm based on bilateral filtering.