data-mining locality-sensitive-hashing reverse-image-search elastic-search bag-of-visual-words k-means-clustering content-based-image-retrieval speeded-up-robust-features jaccard-similarity-estimation sift-descriptors surf-detection canny-edge-detector surf-feature-extraction surf-descriptor computer-vision-python sift-keypoints bag-of-bags-of-words image-retrieval-query min-wise-independent-permutations