Welcome to pHashCoding!
This blog is intended to serve as a place to put things I have been working on. Mostly things related to perceptual hashing along with various other projects. Additionally, I hope these notes prove useful to somebody and perhaps lead to some useful discussion and feedback.
Perceptual Hashing encompasses techniques that involve extracting a concise descriptor of a source signal which can come in any number of multimedia formats - e.g. audio, video, text, etc. It is much like a crypotographic hash (for instance, an md5 checksum), but with an important distinction. Whereas a cryptographic hash affords little robustness with respect to deviations in the signal (i.e. a small change in the signal will yield a big change in the computed checksum), a perceptual hash will preserve a smaller distance between perceptually similar hashes and a greater distance between hashes computed from arbitrary sources.
I hope these notes prove useful to someone. Suggestions and comments are welcome.