bitmap data likeness algorithm

Question

I'd like to compare two bitmaps or parts of bitmap and see how alike they are.

I've came across some likeness algorithms for string data, like Levenshtein distance, and Jaro–Winkler distance. these, obviously, do not help when it comes to bitmap data.

Can anyone suggest an algorithm for comparing how alike bitmaps are?

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EDIT

Thanks for the ideas,links etc.

While all information is helpful in familiarizing with this topic, I'm wondering how to generate images, something more along the lines of this:

Answer 1

You could use Hausdorff image comparison, but be aware that this expects binary images.

Of note, visually similar images may have vastly different underlying pixel representations. Human perception makes computing visual similarity quite difficult. Hausdorff deals well with this by allowing two different images to score highly when the general similarity is the same.

If you want to compute data distances, you can use any distance metric you like and do so directly on the pixels. I'm particularly fond of Mahalanobis distance for these kind of comparisons.