I recently received some scanned pictures which are in a pretty good state, with OK resolution, but they are randomly spattered with a bunch of black dots. These cover everything (clothes, faces, walls, windows, and so on) except for a few very bright areas. I also have no idea how they got there. Here is a sample:
From an information content perspective, I would expect that these dots could probably be removed as they likely have a quite distinct signature. (If they were evenly distributed, for example, I know that a spatial mask on their Fourier transform would do wonders.) Is there some algorithm to remove these artifacts?