[FieldTrip] Missing resolution Information in *vhdr causes ft_preprocessing to return only NaNs

[Karch, Julian]

Hi,

I'm working on a brainvision EEG dataset  which was preprocessed by someone else using Brainvision Analyzer. One part of his preprocessing was to set a new reference. This processing step makes the resolution information in the *vhdr file disappear. Because of that hdr.orig.resolution=NaN for all channels.  As result of that the lines
                calib = diag(hdr.resolution(chanindx));
      % using a sparse multiplication speeds it up
      dat = full(sparse(calib) * dat);
in read_brainvision_eeg produce only NaN. This again results in trials which only contain NaNs.

I do weekly updates of fieldtrip using svn. Because I'm quite sure if was able to read in, using ft_preprocssing, the excact same dataset, even with the same cfg file, earlier this year I checked the modifications for the last half year or so but I couldn't find any change which could have broken it.
My two questions are. How would you handle this problem? Just plug in some random numbers like 0.1 ? Is this an issue with fieldtrip or am I doing something wrong? Were there any changes to the involved functions which could have changed the behavior in that way?

Thanks in advance!

Best,

Julian

Julian Karch
Research Assistant

Center for Lifespan Psychology
MPI for Human Development
Lentzeallee 94, 14195 Berlin, Germany
phone: +49-30-82406-296
fax: +49-30-8249939
web: http://www.mpib-berlin.mpg.de

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