Contrast Enhancement using Sub-Regions Histogram Equalization
Vinay Kumar · 2011
In this paper, a Contrast Enhancement method using Sub-Region Histogram Equalization (CESRHE) is proposed. Histogram Equalization (HE) is widely used for contrast enhancement in digital images. However, this technique is not very well suited to be implemented in consumer electronics, such as television, because the method tends to introduce unnecessary visual deterioration and false contouring due to the significant change in brightness. CESRHE uses linear interpolation method to smooth the histogram in order to moderate the histogram variation effectively. CESRHE separates the intensity range of histogram into k parts and maps the grayscale range based on its Sub-Intensity Range of Output Histogram (SIROH). Then equalizes each sub-region respectively. After that, Intensities of histogram are uniformly redistributed in whole grayscale range. At last, we get the result after the processed sub-regions are composed into one image. The simulation result shows that the algorithm can not only enhance image information effectively but also keep the original image luminance well enough to make it possible to be used in video system directly.