Similar image search by pHash distance in Elasticsearch

Question

Similar image search problem

• Millions of images pHash\'ed and stored in Elasticsearch.
• Format is \"11001101...11\" (length 64), but can be changed (

Answer 1

Here is 64bit solution to @NikoNyrh's answer. Hamming distance can be calculated by just using XOR operator with builtin __popcll function of CUDA.

struct HammingDistanceFilter
{
    const uint64_t _target, _maxDistance;

    HammingDistanceFilter(const uint64_t target, const uint64_t maxDistance) :
            _target(target), _maxDistance(maxDistance) {
    }

    __device__ bool operator()(const uint64_t hash) {
        return __popcll(_target ^ hash) <= _maxDistance;
    }
};