Please use this identifier to cite or link to this item: http://rportal.lib.ntnu.edu.tw:80/handle/77345300/36889
Title: Contrast Enhancement by Automatic and Parameter-Free Piecewise Linear Transformation for Color Images
Authors: 國立臺灣師範大學機電工程學系
Tsai, Chun-Ming
Yeh, Zong-Mu
Issue Date: 1-May-2008
Publisher: IEEE Consumer Electronics Society
Abstract: Conventional contrast enhancement methods have four shortcomings. First, most of them need transformation functions and parameters which are specified manually. Second, most of them are application-oriented methods. Third, most of them are performed on gray level images. Fourth, the histogram equalization (HE) based enhancement methods use non-linear transform function. Thus, this paper proposes an automatic and parameter-free contrast enhancement algorithm for color images. This method includes following steps: First, RGB color space is transformed to HSV color space. Second, image content analysis is used to analyze the image illumination distribution. Third, the original image is enhanced by piecewise linear based enhancement method. Finally, the enhancement image is transformed back to RGB color space. This novel enhancement is automatic and parameter-free. Our experiments included various color images with low and high contrast. Experiment results show that the performance of the proposed method is better than histogram equalization (HE) and its six variations in non-over enhancement and natural clearly revealed. Moreover, the proposed algorithm can be run on an embedded environment (such as mobile device, digital camera, or other consumer products) and processed in real-time system due to its simplicity and efficiently.
URI: http://rportal.lib.ntnu.edu.tw/handle/77345300/36889
ISSN: 0098-3063
Other Identifiers: ntnulib_tp_E0402_01_015
Appears in Collections:教師著作

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