Inverse and direct Arnold transform

Implementation of Arnold transform and its inverse

You have to know that Arnold transform is defined only for squares. If you want to use it in rectangles, you have to firstly add empty rows or colls to make the square. Screenshot represents 5 interations of transform and its inverse.

This implementation doesn't shift the image as the other you can find at File Exchange. Implementation is based on: Digital Image Encryption Algorithm Based on Improved Arnold Transform, by Ma Ding and Fan Jing.