Various Image Enhancement Techniques - A Critical Review

Image Enhancement is very essential and important technique used in image processing. The role of image enhancement is to improve the content visibility of an image. Images in different fields like medical, satellite images, aerial images and even real life pictures suffer from poor contrast and high noise. It is important to only enhance the contrast and reduce the noise to increase image quality. The enhancement technique differs according to various aspects and they can be broadly classified into two categories: Spatial Domain and Frequency domain based techniques. This paper presents a review of image enhancement processing techniques in spatial domain. Also we have categorized processing methods based representative techniques of Image enhancement. Thus this paper helps to evaluate various image enhancement techniques.