Electrical and Computer Engineering, Temple University, Philadelp hia 19122, USA
Abstract-A conventional global contrast enhancement is diffic ult to apply in various images because image quality and contrast enhancement ar e dependent on image characteristics largely. And a local contrast enhancement not only causes a washed-out effect, but also blocks. To solve these drawbacks, this paper derives an optimal global equalization function with variable size b lock based local contrast enhancement. The optimal equalization function makes i t possible to get a good quality image through the global contrast enhancement. The variable size block segmentation is firstly executed using intensity differe nces as a measure of similarity. In the second step, the optimal global equaliza tion function is obtained from the enhanced contrast image having variable size blocks. Conformed experiments have showed that the proposed algorithm produces a visually comfortable result image.
Key words-global contrast enhancement; local contrast e nhancement; optimal equalization function; block segmentation; variable size block
Manuscript Number: 1674-8042(2010)04-0334-04
dio: 10.3969/j.issn.1674-8042.2010.04.08
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