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> The whole idea of a perceptual hash is that the more similar the two hashes are, the more similar the two images are If that is the case, then the word "hash
by enriquto 5y ago
> The whole idea of a perceptual hash is that the more similar the two hashes are, the more similar the two images are
If that is the case, then the word "hash" is terribly mis-applied here.
- tomesco 5y agoHash is applied correctly here. A hash function is "any function that can be used to map data of arbitrary size to fixed-size values." The properties of being a(n) (essentially) unique fingerprint, or of small changes in input causing large changes in output, are properties of cryptographic hashes. Perceptual hashes do not have those properties.
- enriquto 5y agoGood explanation, thanks. I only knew about cryptographic hashes, or those that are used for hash tables where you absolutely do not want to have collisions. Anyhow, I'm not really comfortable with this usage of the word "hash". It is completely opposite of the meaning I'm used to.
- L33tCrown 5y agoMaybe the term fingerprint is better