Identify images with same content in Java

Question

A while ago, I spent some time searching for ways to determine whether two images are identical in order to answer this question. I now face a slightly different problem: I have

Answer 1

I think that the general answer to this question calls for an unsupervised machine learning approach that generates local invariant features - basically, a fancy way of finding hashes that don't change with scaling or rotation - and then running a clustering algorithm. Here are some papers that might be relevant:

• Clustering Near-Duplicate Images in Large Collections
• A Novel Duplicate Images Detection Method Based on PLSA Model
• Efficient image duplicate detection based on image analysis - Tons of stuff in here, since it's some dude's entire PhD thesis