i explain when u use Histogram Equalization. when you get a picture lets say a grey scale one sometimes it is very dark or very bright. that means the colors are very close to one another in thier magnitude. that is the time when histogram equalizatyion come handy. what it does is to spred the colors along the scale which make the picture more viewable because there is a bigger differnce between colors.
example:
- lets say the colors are between 1-100
- and the picture have the colors 99 , 98 , 97
after histogran equalization the colors in the picture will be: 1 , 50 , 100
hope i helped
mayyan