Hi John,
Thanks for getting back to me! This information is very helpful.
It makes complete sense then why the noise covariance is required, but not used in the current implementation. Maybe a short-term solution is to have the code create a "dummy" noise matrix, if noise covariance is not found when attempting to compute the LCMV (i.e., until noise pre-whitening is implemented)?
I also agree that the current beamformer implementation does quite well - anecdotally I've found the source images to be very reasonable, and our recent preprint indicates that spectral derivatives from this approach are highly stable within sessions (https://www.biorxiv.org/content/10.1101/2021.08.31.458384v1).
Thanks again for the helpful response!
Alex