[FieldTrip] ft_channelrepair ignoring missing channels, and destroying grad info on elekta data

[Schoffelen, J.M. (Jan Mathijs)]

Hi Craig,
There are a few open bugs about this on bugzilla.fieldtriptoolbox.org<http://bugzilla.fieldtriptoolbox.org> (2331 and 2404). We are moving away from bugzilla (and try to switch more to github issues), but the the currently open ones still contain some knowledge and history that’s worth to be looked into. Moreover, their resolution might be documented there as well.
I am not sure whether your old esi-e-mailaddress still works, that’s the one with which you are subscribed to bugzilla, but if not, I suggest that you update your e-mailaddress, so that you can check what has been documented regarding the issue you raise. Subsequently, you can work with us towards a solution, which eventually will end up as a pull request on the github repo.

As a side note, I am wondering why you’d want to use ft_channelrepair on MEG data. I could think of the functionality being useful occasionally in EEG, but not in MEG.

Best wishes,

Jan-Mathijs


On 5 Apr 2019, at 19:05, Craig Richter <craiggrichter at gmail.com<mailto:craiggrichter at gmail.com>> wrote:

Hey FTers,

It appears that when a data structure with missing channels is entered into ft_channelrepair, the function is using the input data to determine the sens structure. Since the data is missing channels, the sens structure is also missing these channels, and no interpolation occurs, but no errors are thrown. It states that it was successful. The work-around is to provide a cfg.layout, or cfg.grad to ft_channelrepair, such that ft_fetch_sens does not depend on the input data and returns with a full sensor array, but in this case, the grad info in the data is lost. This appears to be a bug, though http://www.fieldtriptoolbox.org/example/fixing_a_missing_sensor/ would indicate this is the intended behaviour. Perhaps an error, or warning message should be generated. Also, the grad info is largely lost after interpolation except for chanpos and chanori. Is there no way to interpolate all the grad info, such that it is not lost (i.e. tra, and the coil data)?

Any suggestions would be great!

Thanks!

C.

Best,

C.
_______________________________________________
fieldtrip mailing list
https://mailman.science.ru.nl/mailman/listinfo/fieldtrip
https://doi.org/10.1371/journal.pcbi.1002202

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.science.ru.nl/pipermail/fieldtrip/attachments/20190406/60c4a33f/attachment-0002.html>
-------------- next part --------------
_______________________________________________
fieldtrip mailing list
https://mailman.science.ru.nl/mailman/listinfo/fieldtrip
https://doi.org/10.1371/journal.pcbi.1002202