Matlab has this command:

[J,T] = histeq(I);

[___,T] = histeq(___) also returns the transformation T that maps the gray component of the input grayscale image

I use GNU Octave, version 6.4.0. But the histeq command of Octave does not have that output argument. How I can obtain the transformation of histeq and plot it in Octave?

CodePudding user response：

The mapping T is given by the cdf of the normalized histogram (see Histogram equalization implementation.

This mapping is stored in the variable Icdf in histeq.m. Since the code for this function (aside from input checking) is only 6 lines, it would be a simple matter to clone the function to access T.