[pippy360]

>I was wondering, how did you determine your criteria for matching

Yeah, the query image is broken into a number of fragments and then the hash of each fragment/triangle is checked against the hashes stored in the database using a nearest neighbor search (well you find any neighbors within a certain distance/threshold, I found a hamming distance of 8 to be a pretty good threshold).

Currently only one fragment of the query image needs to match a database image for the images to be considered a match. You could also put some threshold on the number of fragments that need to match but this is only a proof of concept I haven't had time to find the perfect combination yet.

>could this be extended to colour transformations

Yeah, actually after you have re-transformed the triangles to be equilateral you can apply a lot of other techniques to future improve the search. You can even use NON-affine transformation partial image matching on the triangles to match fragments that only partially match fragments stored in the database.