[Mne_analysis] Regularization of the noise covariance matrix with tSSSed data

Alexandre Gramfort alexandre.gramfort at telecom-paristech.fr
Fri Jul 18 07:52:13 EDT 2014
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hi Ying,

try at first without regularizing. MNE should detect the rank
automatically when whitening. It's however possible that tSSS makes
rank estimation difficult due to slight head positions changes.

maybe Sheraz or Rey can share their insights too.


On Thu, Jul 17, 2014 at 6:43 PM, Ying Yang
<evergreenlifeyangying at gmail.com> wrote:
> Hi MNE experts,
> I am wondering whether it is common to regularize the noise covariance
> matrix for tSSSed data. Since tSSS may reduce the rank of the sensor data,
> (in my case to 64),  the covariance matrix is singular too.  As a result,
> the whitened forward gain matrix had a lot of zeros.
>  In this case, is it better to regularize the noise covariance matrix, or to
> leave it intact such that the rank of noise matches the rank of  "signal"?
> Thanks in advance!
> Best,
> Ying
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