1 | initial version |
Hopefully this will help you understand. http://www.jot.fm/issues/issue_2010_03/column2.pdf
In short, using the Discrete Fourier Transform (DFT), you can compute the whole cross correlation two DFTs and a multiplication. If all you are doing is cross correlation, you're done. Computing the SQDIFF or CCOEFF or normalizing requires some more work, which happens in the common_matchTemplate function.