A method of local enhancement based on fuzzy set theory

Due to the effect of illumination, some image contrasts are often not uniform. Image enhancement becomes an important problem in these images processing. This paper presents a method of local enhancement based on the fuzzy set theory to improve the image contrast. The method includes the following three steps: 1) the image is divided into sectors; 2) a kind of fuzzy enhancement method is implemented on each sector; and 3) the maximum and minimum gray levels are constants within sectors, but different for the various sectors. Finally, we re-divide the image into sectors with more pixels, and repeat step 1 and 2, until the whole image includes only one sector. Experimental result shows that the method of local enhancement based on fuzzy enhancement is better than the conventional fuzzy methods