Image enhancement with the application of local and global enhancement methods for dark images

Abstract

Image enhancement is a technique used to get a better quality of an image in terms of its clarity, brightness and to give the human eye comfortable to look at. There are different types of techniques to give good quality of an image. Global image contrast enhancement is one of the most commonly used technique to enhance the quality of an image, but it has some disadvantages with the fact that it does not consider the local details of an image. Local details of an image are very important while analyzing an image, which is that of the scientific study of an image like the image taken from planetary bodies, satellite image and medical images. Local details of an image are very important for diagnosing a particular ailment. When either local contrast enhancement or global contrast enhancement is used alone, there is loss of brightness of the image. In order to address and reduce this discrepancy of individual enhancement methods, a new method is presented in this paper, that uses both local and global enhancement methods on the same image. First, the image is locally enhanced and the output is again processed by the global enhancement method thereby giving a properly enhanced image without losing the brightness of the image. This enhancement method is simulated in MATLAB and results are verified on the parameters of image quality.