As technology is evolving at a high rate in every field and in image processing as well. With the increasing need of high definition images, new techniques are emerging in image processing and for that image enhancement is playing a pivotal role. Images suffer from blurring, noise, poor contrast, poor brightness etc. which degrades the quality of the image so in order to overcome all this, image enhancement is used. Out of numerous complex techniques selection is done on the basis of area where processed image is required. It uses a „transform‟ to improve the visual quality, contrast, brightness of an image. In medical, satellite, video conferencing, aerial images, real life photographs etc. improvement of the contrast of an image is demanded, soit can provide high quality images in different fields. A lot of work has been done by researchers in this very fieldMany methods and algorithms has been designed for the same. This paper provides an overview of various techniques used for image enhancement which includes spatial and frequency domain methods. This paper also involves other techniques falling under the category of spatial and frequency domain and compare their results as well.