Piecewise histogram equalization based image enhancement

Abstract

Piecewise histogram equalization（Piecewise HE） was proposed,which combines the benefits of contrast stretching and existing histogram equalization.The swallow of saturation and brightness is avoided in the enhanced image by a piecewise linear mapping function,which combines with the mean and standard deviation of the histogram,and the parameters selection of Piecewise HE is explored when over-enhancement existed.The experimental results have demonstrated that the proposed method can enhance the images effectively,which avoids the swallow and over-enhancement problems of the existing histogram equalization methods.The proposed method not only preserves the original details,but also has a more natural visual effect in the enhanced image.

Keywords

• image enhancement
• histogram equalization
• piecewise equalization
• detail preserving