[irixusr]

I think the idea is that an image has a certain amount of self similarity. I.e. skin looks like skin. So the algorithm learns how skin is supposed to look like by looking at all the skin. So every wrinkle is improved by looking at every other wrinkle as opposed to just the pixles in an immediate vicinity.

Now replace "wrinkle" for "patch" and sprinkle some crazy stats and machine learning to get the idea to work.