Decent Video on Cross Correlation/Auto-correlation
Posted: Mon Jul 29, 2019 2:00 am
Older (2014) video, and the environment is MATLAB, not Ruby, but a good run-through on the "how":
https://www.youtube.com/watch?v=ErtPBvEnQZc
https://www.youtube.com/watch?v=ErtPBvEnQZc