Original author here. Thanks for the spacial data structures link, I'll look into it.
The correlations are done in the frequency domain. And, although I didn't look into it, I suspect they have pretty good algorithms to compute the correlations themselves. At least they have very smart people working on that.
The correlations are done in the frequency domain. And, although I didn't look into it, I suspect they have pretty good algorithms to compute the correlations themselves. At least they have very smart people working on that.