Adaptive Histogram Equalization

There are a number of non-linear methods for enhancing the details in images. One effective method is adaptive histogram equalization which has been studied extensively by Prof. Pizer at UNC-CH. Here, the image is partitioned N by N subregions and the histogram for each region is calculated and used to perform local image enhancement. The program ahe has a number of options which control the number of subregions (and hence the degree of enhancement). When only one region is used, ahe is the same as greymap -h which does global histogram equalization. (see code)

Command Usage

ahe [options] infile outfile
    [-d]    Print debugging information
    [-n #]  Number of subregions in x and y (default 3)

Example

ahe -n 5 input.im ahe0.im
disp input.im ahe0.im

ahe -n 10 input.im ahe1.im
ahe -n 20 input.im ahe2.im
disp ahe1.im ahe2.im