title: Visual Contrast Enhancement Algorithm Based on Histogram Equalization.
abstract: Image enhancement techniques primarily improve the contrast of an image to lend it a better appearance. One of the popular enhancement methods is histogram equalization (HE) because of its simplicity and effectiveness. However, it is rarely applied to consumer electronics products because it can cause excessive contrast enhancement and feature loss problems. These problems make the images processed by HE look unnatural and introduce unwanted artifacts in them. In this study, a visual contrast enhancement algorithm (VCEA) based on HE is proposed. VCEA considers the requirements of the human visual perception in order to address the drawbacks of HE. It effectively solves the excessive contrast enhancement problem by adjusting the spaces between two adjacent gray values of the HE histogram. In addition, VCEA reduces the effects of the feature loss problem by using the obtained spaces. Furthermore, VCEA enhances the detailed textures of an image to generate an enhanced image with better visual quality. Experimental results show that images obtained by applying VCEA have higher contrast and are more suited to human visual perception than those processed by HE and other HE-based methods.
authors.affiliation: School of Defense Science, Chung Cheng Institute of Technology, National Defense University, Taoyuan 33551, Taiwan. chihchungting@gmail.com.
authors.forename: Chih-Chung
authors.initials: CC
authors.lastname: Ting
authors.affiliation: Institute of Electrical and Control Engineering, National Chiao Tung University, Hsinchu 30010, Taiwan. bwu@cssp.cn.nctu.edu.tw.
authors.forename: Bing-Fei
authors.initials: BF
authors.lastname: Wu
authors.affiliation: Institute of Electrical and Control Engineering, National Chiao Tung University, Hsinchu 30010, Taiwan. mlchung.ece96g@g2.nctu.edu.tw.
authors.forename: Meng-Liang
authors.initials: ML
authors.lastname: Chung
authors.affiliation: Department of Electrical and Electronic Engineering, Chung Cheng Institute of Technology, National Defense University, Taoyuan 33551, Taiwan. davidchiu@ndu.edu.tw.
authors.forename: Chung-Cheng
authors.initials: CC
authors.lastname: Chiu
authors.affiliation: Department of Electrical and Electronic Engineering, Chung Cheng Institute of Technology, National Defense University, Taoyuan 33551, Taiwan. m0919048774@yahoo.com.tw.
authors.forename: Ya-Ching
authors.initials: YC
authors.lastname: Wu
keywords: contrast enhancement; dynamic range; histogram equalization (HE); just-noticeable difference (JND)