I don't know of an existing tool, but I have lots of experience with 2-D image processing. I have some ideas as to how it could be done somewhat more efficient

I don't know of an existing tool, but I have lots of experience with 2-D image processing. I have some ideas as to how it could be done somewhat more efficiently than brute-force. If you're really freaking, perhaps I could flog my consulting service, and write the program for you under contract?