Hashing Algorithms

Open-source algorithms for turning content into anonymous digital fingerprints called "hashes".

PDQ

A perceptual hasher: it tries to match images which people perceive as similar. It is a spectral hashing algorithm, namely, it uses a Discrete Cosine Transform (DCT). One of its outputs is a quality metric, enabling systems to filter junky/featureless images out of processing.

vPDQ

vPDQ (Video PDQ) is a video-similarity-detection algorithm, which uses the PDQ image similarity algorithm on video frames to measure the similarity of videos.

TMK

Temporal Match Kernel is a video-similarity-detection algorithm produced in conjunction with Facebook AI Research ('FAIR')