histogram equalization examples

reference: 点击打开链接 https://blog.csdn.net/xiajun07061225/article/details/6910129

example:

original image:

after histogram:

we can see that the contrast of the latter image is higher than that of the original image.

important principles:

1. we need to guarantee that during this process, the transformation T is monotonically increasing.

2. we use the cumulative distribution function(cdf) to make the the gray-level have a uniform distribution to satisfy the first requiement.