- Build a database of image hashes using said library
- Use an algorithm that allows you to lookup hashes by distance. In the case of hamming distance (used by many image hashes) you can just throw them in MySQL. You could also use any of the nearest neighbours search algorithms like k Nearest Neighbours or locality sensitive hashing (you'd want one of these for larger datasets)
Really though it's not too hard to whip something up yourself. I did it for a bunch of those 'booru' sites (roughly 3 million images) like this:
- Find image hashing library (I used https://github.com/JohannesBuchner/imagehash but there's a nice series of articles here http://www.hackerfactor.com/blog/?/archives/432-Looks-Like-I... if you want to implement your own)
- Build a database of image hashes using said library
- Use an algorithm that allows you to lookup hashes by distance. In the case of hamming distance (used by many image hashes) you can just throw them in MySQL. You could also use any of the nearest neighbours search algorithms like k Nearest Neighbours or locality sensitive hashing (you'd want one of these for larger datasets)