A Comparative Investigation of Different Image Enhancement Techniques Using Histogram Equalization

To Improve contrast and preserving brightness is the most important task when enhancing the quality of a digital image by using histogram equalization technique. A number of brightness preserving techniques are developed and applied in digital images. Each technique has its own degree of excellence. Only one technique cannot be used in all types of digital image. Image can be clicked in different environment and conditions. So, on the basis of the quality of image, a specific technique is selected. But how to select the right technique to enhance the quality of image is the important question. To solve the problem, in this paper the most useful and popular techniques are compared on the basis of certain parameters so that the most suitable technique can be sorted out for the image of interest. Therefore, four such techniques based on Histogram Equalization viz CHE (Conventional Histogram Equalization), BBHE (Brightness Preserving Bi-Histogram Equalization), DSIHE (Dual Sub-Image Histogram Equalization) and MMBEBHE (Minimum Mean Brightness Error Bi-HE), are compared. For quantitative comparison four mathematical quantities i. e. PSNR, MSE, Entropy and AMBE are measured.