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Bug 833 - minimumnormestimate should work with lambda in an interpretable range
| Status | CLOSED FIXED |
| Reported | 2011-07-19 14:48:00 +0200 |
| Modified | 2012-03-21 15:42:55 +0100 |
| Product: | FieldTrip |
| Component: | inverse |
| Version: | unspecified |
| Hardware: | All |
| Operating System: | All |
| Importance: | P1 enhancement |
| Assigned to: | Jan-Mathijs Schoffelen |
| URL: | |
| Tags: | |
| Depends on: | |
| Blocks: | |
| See also: |
Jan-Mathijs Schoffelen - 2011-07-19 14:48:27 +0200
-Right now, the influence of the lambda is determined by the magnitude of the noise covariance matrix, and the magnitude of the gram-matrix (including the source priors). -Check how this is done in the MNE-suite Implement something similar
Jan-Mathijs Schoffelen - 2012-02-06 16:48:27 +0100
MNE-suite allows for the spatial filter to be computed based on prewhitened leadfields, where the leadfields are prewhitened with an estimate of C^-1/2 where C is the noise covariance estimate. In a next step, the source covariance estimate is tailored such that the trace of the A*R*A' matrix is the same as the trace of I, where A is the prewhitened leadfield matrix and R the source covariance matrix. As a consequence of the prewhitening, the lambda parameter can take 'normal' values. According to the documentation can be taken as ~ 1/SNR I implement this in minimumnormestimate as: cfg.mne.prewhiten = 'yes';
Jan-Mathijs Schoffelen - 2012-02-07 16:17:13 +0100
.