A Novel Approach for Contrast Enhancement in Biomedical Images Based on Histogram Equalization

This paper presents a novel technique to increase the quality of medical images based on histogram equalization. In the proposed method first we have applied a noise reduction method and then we apply some suitable preprocessing on histogram of the medical images and after that histogram equalization has been applied on the new histogram. Our proposed method in despite of its simplicity has better results in compare to other usual methods based on histogram equalization. The quality of resulted images after applying our proposed methods has been tested on a database (medical images) with a confirmed criterion by viewer. Also we have considered a mathematical criterion for comparing our proposed algorithm with other available methods for contrast enhancement. Results show the better efficiency of the proposed method.

1. Introduction

Medical imaging is one of the best techniques for monitoring the person's health condition which is used widely nowadays. Also some of diseases can be detected using medical imaging methods. One of the problems that physicians encounter with it using medical images is low quality of the medical images. This low quality is caused to difficulty in diagnosis. So it is necessary to improve the quality of the medical images. There are so many methods for medical image enhancement to make a better perception from medical images. Various methods have been suggested for increasing medical image's quality in recently years. Histogram processing is one of the most important digital image processing techniques and it is widely used for increasing medical image's quality. Because the simplicity and better efficiency of the histogram based algorithms, these algorithms are widely used for contrast enhancement of images. Also it should be mentioned that histogram based techniques are much less expensive in compare to the other methods [1].