A New Method for Image Contrast Enhancement Based on Automatic Specification of Local Histograms
Iyad F. Jafar, Hao Ying · 2007
The histogram equalization (HE) method is widely used for image contrast enhancement. While it can enhance the overall contrast, the inherent dependence of its transformation function on the global content of the image limits its ability to enhance local details at the same time. Furthermore, using the method to reform the image histogram into a uniform one usually results in a significant change in the image brightness and saturation artifacts, specifically in low contrast images. One extension for HE is the local histogram equalization (LHE) method that processes the image on block-by-block basis and uses the transformation function of HE for that block to modify its center pixel. Although the LHE method can enhance image details, it often causes unacceptable and unnatural image modification due to noise amplification, especially in smooth regions. In this paper, we propose a new