Abstract: Histogram equalization,as a special histogram specification method,is an effective algorithm for image contrast enhancement.But it stretches the dynamic range of the image’s histogram which usually makes some of the uniform regions of the output image become saturated with high light.An image specification algorithm based on Gaussian PDF has been proposed recently.However,it is unsatisfactory for image enhancement due to its worse sense of hierarchy.Based on this,an image specification algorithm based on multi-peaks Gaussian function was proposed in this paper.In this form,local-means and local-variances can be estimated respectively with the method of derivative.A key feature of the algorithm is that varying the parameters of local-variances can enhance the image contrast selectively and locally.The resulting process can broaden a range of image contrast.For color image enhancement,the proposed algorithm can be the provisions of the R,G,B three sub image of color image and then effectively combine R,G and B with the color recovery factor on the habit of human vision.Both experimental results and theoretical analysis demonstrate the proposed algorithm is optical effective.

Key words: Image enhancement,Histogram equalization,Multi-peaks Gaussian function,Derivation,Histogram specification,Color recovery factor