New hue preserving algorithm for color image enhancement

After analyzing Retinex theory and its typical algorithm for color image enhancement,a new hue preserving algorithm for color image enhancement was presented.Firstly,it utilized a nonlinear sigmoid transfer function to intensify the image brightness component at multi-scale,and then brightness gain curved surface was acquired by reinforcing the image local contrast,finally the original color image RGB three components were enhanced at the same proportion by brightness gain curved surface,which ensured the hue was constant and undistorted.Experimental results of the proposed algorithm and other algorithms were compared and analyzed to illustrate the effectiveness of the proposed method.