Region-based weighted histogram and its application to image contrast enhancement

Histogram-based techniques are useful for image enhancement. However, these techniques often fail to produce satisfactory results for some low-contrast images. In this paper, we propose a new form of histogram for image contrast enhancement. The input image is first divided into several equal-sized regions according to the intensities of the gradients, their corresponding statistical values of gray levels are then modified respectively, and finally the processed histogram for the whole image is obtained by summation of all the weighted values of regions. Experimental results show that the performance of many histogram-based techniques can be improved significantly by using our new histogram.