Image Contrast Enhancement method based on Fuzzy Logic and Histogram Equalization

Histogram Equalization is a very effective and most widely used method to enhance the contrast of images. But in some situations where it is necessary to preserve the brightest factor of an image , histogram equalization does not works well and gives un-natural resultant images that are not desirable. A novel histogram equalization technique based on fuzzy logic is introduced in this paper. In the first step, Fuzzy histogram is computed based on fuzzy computation techniques to handle the inexactness of original values in a better way as compared to crisp histogram computation techniques. In the second step, the fuzzy histogram is decomposed into two sub-histograms based on the median value of the original image and then histogram equalization is applied on both histograms independently to maintain the luminance of the image. In the last step processed sub-images are composed into one image to produce the result. The experimental results show that the proposed method gives better result as compared to many existing methods and removes the washed out appearance of the images. The proposed method preserves the brightness of the original image.