A novel fuzzy wavelet approach to contrast enhancement

This paper presents a novel contrast enhancement approach based on wavelet transform and fuzzy logic. We first normalize the low contrast image to reduce the effects of different illuminations. Then we choose a specific wavelet transform to convert the normalized image and obtain wavelet coefficients. The low-pass coefficients are fuzzified by the linear operator, and we use both the global and local information to define and enhance the image's global contrast. We utilize nonlinear operator on high-pass coefficients to enhance the details of images. Finally, the inverse wavelet transform is applied to map the result into space domain. The experimental results demonstrate that the approach is very effective in enhancing the low contrast image.