A Combination of Local and Global Method for Contrast Image Enhancement - A Review Approach

Image enhancement is used to improve the poor quality of an image to make it useful for human and for machine use. This paper suggests two methods for contrast image enhancement to preserve brightness of an image. This method is applied on 2D histogram. In 2D histogram preserving color value is very important part. Local feature enhancement technique is used to improve local features of an image. Local feature enhancement technique is used to sharpen the edges. Contrast Streching with its brightness factor is used to improve the global features of an image. This two method are used in combination that is first take the weighted difference of two methods .The second method is that first we will going to use local feature enhancement technique obtain the output of it and on that output apply Contrast Streching with brightness factor and obtain the final output that is enhanced image. In this we are also exploring the new ideas of local and global method for contrast image enhancement. Global Contrast Image Enhancement is basically done by three ways Histogram Equalization, Contrast Stretching and Unsharp masking and Edge Sharpening .We will going to use the useful part of all these three methods and try to develop a new method which is combination of three method and that method we will also going to use in this work. The qualitative analysis of this method is done by using various factors, they are discrete entropy, peak signal to noise ratio, image enhancement factor and many more. The comparative analysis is done with another existing method.