Contrast Enhancement in Palm Bone Image Using Quad-Histogram Equalization

Histogram equalization is widely used for contrast enhancement of given images. The traditional histogram equalization technique usually results in extreme contrast enhancement, which leads to an unnatural look. In this paper, the mean-variance analysis method is employed to partition the grey scale image into four sub images for individual image. A quad-histogram equalization technique is proposed to enhance the contrast of the palm bone X-ray radiographs. Experimental results using the proposed method show that our algorithm is better than the global histogram equalization (GHE) technique and brightness preserving bi-histogram equalization (BBHE) technique.