HE (Histogram Equalization) is a fundamental method in the field of image enhancement

the research and improvement about which is very significant. First

this paper analyzes the disadvantages of the classical HE algorithm and summarizes five kinds of image enhancement techniques based on HE. Then

two kinds of improved methods are proposed aiming at the disadvantages of the classical HE algorithm

the techniques of the peak clipping and the edge information fusion are introduced. Finally

underexposure and overexposure images are selected to verify the algorithms' properties

the standard of efficient image objective quality assessment is selected to evaluate the experimental results. The assessment of image subjective and objective quality shows the algorithms this paper proposes have the characteristics of better results

less input parameters and so on.