Color Image Enhancement Method with Variable Emphasis Degree

Hiromu ENDO  Akira TAGUCHI  

IEICE TRANSACTIONS on Fundamentals of Electronics, Communications and Computer Sciences   Vol.E101-A   No.4   pp.713-722
Publication Date: 2018/04/01
Online ISSN: 1745-1337
DOI: 10.1587/transfun.E101.A.713
Type of Manuscript: PAPER
Category: Image
color image enhancement,  differential gray-level histogram equalization,  intensity saturation,  contrast,  colorfulness,  

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In this paper, we propose a new enhancement method for color images. In color image processing, hue preserving is required. The proposed method is performed into HSI color space whose gamut is same as RGB color space. The differential gray-level histogram equalization (DHE) is effective for gray scale images. The proposed method is an extension version of the DHE for color images, and furthermore, the enhancement degree is variable by introducing two parameters. Since our processing method is applied to not only intensity but also saturation, the contrast and the colorfulness of the output image can be varied. It is an important issue how to determine the two parameters. Thus, we give the guideline for how to decide the two parameters. By using the guideline, users can easily obtain their own enhancement images.