Combined Linear And Nonlinear Image Enhancement

Image Enhancement is a commonly used approach for de-blurring the image. In general, image enhancement is to increase the contrast and remove noise so that the processed image is more suitable for special applications. There are two approaches for this – linear and nonlinear. Each method has its own advantages and disadvantages. But studies over the years showed that real applications use both methods simultaneously. So in this paper, we propose an approach which combines linear and nonlinear image enhancement. For linear image enhancement we used Piecewise Linear contrast enhancement and for nonlinear we used method based on opportunity cost with some modifications. At the end, we proposed a combination algorithm which combines the results of both methods, and the results show that the combination of these methods are better than each alone. We used PSNR [6] as a basis for determining the quality of images. Keywords— piecewise linear contrast enhancement, nonlinear image enhancement, opportunity costs, clipping, scaling