A Groovy, performance enhanced implementation of pHash based off of https://code.google.com/p/ironchef-team21/source/browse/ironchef_team21/src/ImagePHash.java?r=75856e07bb89645d0e56820d6e79f8219a06bfb7

Notably, this implementation reduces hashing time from ~1.5-2s to ~200-250ms. A simple test and sample image is included.

Some additional ideas for enhancements can be found at:

• http://nekkidphpprogrammer.blogspot.fi/2014/02/yes-it-is-perfect-now.html
• http://www.hackerfactor.com/blog/index.php?/archives/432-Looks-Like-It.html (comments section)

Test output:

Old hash took 2265 ms

Hash: 0111000111001110011100011110111001111111011001100

New hash took 244 ms

Hash: 0111000111001110011100011110111001111111011001100