A color image enhancement method with a high regard for restoration of skin color

Hue (H), saturation (S) and intensity (I) are the attributes of color. Therefore, a lot of color image enhancement techniques are performed in HSI color space. In this paper, a new color image contrast enhancement method is proposed in HSI color space. Histogram equalization (HE) is a popular technique for contrast enhancement of images. It is the most commonly used method due to its simplicity and comparatively better performance on almost all types of images. However, HE shows unnatural results for images with large background. In order to improve this drawback of HE, HE with variable enhancement degree (HE-VED) is introduced. The enhancement degree of HE-VED is controlled by one parameter. Then, HE-VED is applied to saturation and intensity histograms separately. In this paper, we aimed mainly at natural color images include human faces. In the kind of image, it is necessary to describe skin color accurately. Thus, we adjust a parameter of HE-VED, in order to restore the skin color of human faces.