phash

We have a database of images where I have calculated the PHASH using Dr. Neal Krawetz's method as implemented by David Oftedal . Part of the sample code calculates the difference between these longs is here: ulong hash1 = AverageHash(theImage); ulong hash2 = AverageHash(theOtherImage); uint BitCount(ulong theNumber) { uint count = 0; for (; theNumber > 0; theNumber >>= 8) { count += bitCounts[(theNumber & 0xFF)]; } return count; } Console.WriteLine("Similarity: " + ((64 - BitCount(hash1 ^ hash2)) * 100.0) / 64.0 + "%"); The challenge is that I only know one of these hashes and I want to query

Similar image search problem Millions of images pHash 'ed and stored in Elasticsearch. Format is "11001101...11" (length 64), but can be changed (better not). Given subject image's hash "100111..10" we want to find all similar image hashes in Elasticsearch index within hamming distance of 8 . Of course, query can return images with greater distance than 8 and script in Elasticsearch or outside can filter the result set. But total search time must be within 1 second or so. Our current mapping Each document has nested images field that contains image hashes: { "images": { "type": "nested",