These IMAGEJ plugins are made to equalize or stretch the histogram of a colored picture and are supposed to be used on RGB images, like shown in the directory "img_tests".

To download IMAGEJ : https://github.com/imagej . To execute these plugins, put them into the directory /home/.imagej/plugins, open an image in the software IMAGEJ, then click "plugins" -> "compile and run", search and select the plugin you want to use.