A Review of Contrast Enhancement Techniques in Digital Image Processing

Image enhancement has a fundamental piece in digital image processing. Images like satellite images, aeronautical images, oceanography images, medical images and real-life images suffer bad contrast and noise. The purpose of image enhancement is to enhance the contrast and remove the noise to raise image quality. The image enhancement technique especially contrasts enhancement distinct from one field to another depending on its objective. In this paper, a review of various contrast enhancement techniques has been done. The techniques presented begin from conventional to modern techniques. A study shows that the small values of Mean Brightness Error (MBE) and Speckle Noise Strength (SNS) can maintain an average of lighting and enhance the contrast well. By combining several techniques, not only enhances the contrast but also increases the sharpness of the image. Therefore, the selection of appropriate techniques can increase the image quality results. Furthermore, from the results of this review will be used as a reference for researchers to process images that have nonuniform illumination.