[mctx]

Have you looked at https://github.com/dermotte/lire? This plugin for ElasticSearch uses it: https://github.com/kzwang/elasticsearch-image

[kaivi]

Looks like it does all kinds of tricks at once -- histograms, SIFT/SURF features and edge patterns. I was looking for a simpler solution, like an effective MVP-tree implementation for perceptual hashes. Wouldn't that be faster and overall better?