[FieldTrip] lambda regularization using Neuromag data
hjpark05 at snu.ac.kr
Tue Oct 23 16:06:10 CEST 2012
I'm working on LCMV beamforming using Neuromag data applied with Maxfilter.
I am using 204 gradiometer sensors.
I have rank deficiency problem, maybe because of Maxfilter since it reduces
When I checked the data, the rank is 60.
I removed EOG and ECG components using ICA.
2 or 3 components in sum in most subjects.
So for some, the rank is 58, for some, it's 57.
When I tested with different lambda from 0% to 10%, (or above, even 100%), I
got the same warning ('covariance matrix is rank deficient').
Does anyone have suggestions for which lambda is most appropriate in this
case? Or any other useful advice/experience for how to apply beamforming in
combination with Maxfilter?
Thank you in advance.
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