Contrast enhancement and brightness preservation using global-local image enhancement techniques

The contrast enhancement technique plays a vital role in image processing to bring out the information that exists within low dynamic range of that gray level image. To improve the quality of an image, it required to perform the operations like contrast enhancement and reduction or removal of noise. This paper proposed a concept of contrast enhancement using the global mean of entire image and local mean of 3×3 sub images. Local mean filter is used to smooth the image by taking the mean value of the pixels surrounding the center pixel within the image. Experimental results based on subjective and objective evaluation have demonstrated that the proposed algorithm is able to increase the brightness of an input gray level image.