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Bug 1338 - channelrepair not possible after componentanalysis and -rejection

Reported 2012-02-22 12:16:00 +0100
Modified 2012-08-23 10:49:37 +0200
Product: FieldTrip
Component: documentation
Version: unspecified
Hardware: PC
Operating System: Windows
Importance: P3 normal
Assigned to: Jan-Mathijs Schoffelen
Depends on: 1249
See also:

Jörn M. Horschig - 2012-02-22 12:16:10 +0100

Hi guys, For those that are interested I figured out the problem. Somewhere in the process of running component analysis and then component rejection, fieldtrip was taking .chanpos and .chanori in my .grad field and replacing all the values with NaNs. I fixed the problem by adding cleandata.grad = data.grad just after component rejection. It would be great though, if some one could look at the ft_componentanalysis and ft_rejectcomponent functions and figure out why the grad information is being lost. Thanks! Keith

Jan-Mathijs Schoffelen - 2012-02-24 09:05:50 +0100

This is intended behaviour. Components don't have 'positions', so once you project to component space the position info is lost. The only way to get it back, is to use a fresh grad-structure.

Jörn M. Horschig - 2012-02-24 10:29:34 +0100

as far as I understood, Keith rejected components and then went from component-space back to sensor-space. Then, he wanted to interpolate sensors. Since ft_rejectcomponent transforms comp back to sensor-space data there should be sensor positions as well, shouldn't it?

Jörn M. Horschig - 2012-02-24 10:31:03 +0100

after writing this, I vaguely remember that we had a discussion about this in one of the FT meetings Maybe it should be just be stated somewhere that sensor position information will be removed in componentanalysis...

Jan-Mathijs Schoffelen - 2012-02-24 11:45:16 +0100


Jan-Mathijs Schoffelen - 2012-07-17 13:03:23 +0200

revision 6270: throw explicit error when there are nans in the chanpos