[Eeglablist] ICA and covariance matrix for CSP

[Makoto Miyakoshi]

Dear Bethel,

Sounds like it is because of reduced rank. Please try that you also discard
the same number of channels after IC rejection to see what happens.

Makoto


2013/4/23 Bethel Osuagwu <b.osuagwu.1 at research.gla.ac.uk>

> Hi Everyone,
>
> I have noticed that after using ICA to remove artifact in my signal, I can
> no longer compute the covariance matrices needed for common spatial pattern
> without matlab giving me warning regarding the accuracy of the estimated
> matrix. Indeed the estimated matrix is not accurate. This does not happen
> if I use only a small subset of my channels after removing noise with ICA.
>  If I do not use ICA at all the warning disappears.
>
> I want to ask if anybody knows why ICA causes this issue and how I can fix
> it?
>
> Thanks a lot.
> Bethel Osuagwu
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-- 
Makoto Miyakoshi
Swartz Center for Computational Neuroscience
Institute for Neural Computation, University of California San Diego
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