Histogram Equalization

In trichromatic images the image is processed for each color independently. In the process, we first count the number of pixels corresponding to each
of the 256 intensity levels for each color, R, G and B. Then, for each color, we calculated the transform function values,, for each intensity level, where the
transformation function is:
n: number of total pixels
Afterwards, we mapped values from [0,1] range to the range of [0,255] using the formula :

As a final step, we replaced each value in the image with its corresponding value.
Histograms of the original and equalized images are in this page.
If we were to process graylevel images, we needn't to repeat the procedure three times; we would apply the algorithm just once.

Samples

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