Medical Image Enhancement with Brightness Preserving Based on Local Contrast Stretching and Global Dynamic Histogram Equalization

Medical images such as MRI image, mammogram images, X-ray images, CT-scan images provide appropriate information regarding human brain soft tissue, cancer, stroke and various other diseases. These images help doctors to identify the diseases easily. But these images may suffer from very low contrast ratio and to improve contrast of such image we used hybrid technique which is the combination of contrast stretching (CS) and Brightness Preserving Dynamic Histogram Equalization (BPDHE). Our proposed method work as follows: In the first step, we applied pre-processing to remove noises present in images then we estimated accurate background surface and obtained new foreground image by subtracting this estimated background from the original image. We carried out local contrast stretching method on new image which containing only foreground object. Finally, after combining the background and enhanced foreground image we apply global BPDHE method to enhance image. The experiments were performed on various low contrast medical images. Experiments show more accurate results than other contrast enhancement methods.