I've been exposed via StackOverflow to pHash, a C++ perceptual hash library for audio, video, images, and text fingerprinting - recently with preliminary bindings for PHP, C# and Java.
I'm interested in studying these algorithms and I'm wondering if there are any open-source pure Python or PHP implementations of the same / similar algorithm? This would make my life a lot easier.
I have been searching on Google, but not much has come up. Since it seems you want the code for academic purposes, I would suggest:
Hit Wikipedia - look up each algorithm and get a feel for how it works
Check the pHash site's mailing list - I doubt you are the first person to be curious.
Email the authors and ask what sources they used (books, papers, etc.)
Use bookstore, library, etc. to find your own sources
I personally find that studying code is very ineffective at teaching algorithms (at first anyway, until you have a feel for the overall process).
来源:https://stackoverflow.com/questions/3216901/perceptual-hash-algorithms-in-python-or-php