[Eeglablist] bva io plugin scaling

[basile pinsard]

Hi Andreas,
thanks for your quick reply.
Sorry, you are right the code is correct, I was trying to investigate on
why I get higher amplitude in a channel which has a different scaling and
got mixed in the code, but it is certainly a matter of acquisition setup.
Thanks for your help.

Best,
Basile

On Mon, Sep 28, 2015 at 4:42 AM, Andreas Widmann <widmann at uni-leipzig.de>
wrote:

> Hi Basile,
>
> your input is appreciated. To report potential bugs, please file a report
> at the EEGLAB bugzilla (https://sccn.ucsd.edu/bugzilla/) *including* a
> description of the problem you perceived and instructions how to replicate
> the problem (optimally including a small sample file!). For bva-io
> alternatively you could create an issue at the Github repository (
> https://github.com/widmann/bva-io).
>
> Sorry, from the code you sent I unfortunately cannot replicate or
> understand the problem. The ref, scale, and unit fields are intentionally
> not stored in the EEG.chanlocs structure (for compatibility reasons).
> Scaling is done in line 355 and does not refer to the EEG.chanlocs
> structure (EEG.data(chan, :) = EEG.data(chan, :) * chanlocs(chan).scale;)
>
> Best,
> Andreas
>
> > Am 25.09.2015 um 17:34 schrieb basile pinsard <basile.pinsard at gmail.com
> >:
> >
> > Hi all,
> > The bva-io plugin had a bug which prevent correct scaling of the data.
> > most of the operation on chanlocs was not stored in EEG structure
> > I mainly changed the lines  117-136 of pop_loadbv.m for the following to
> restore correct scaling.
> >
> >
> > if isfield(hdr, 'channelinfos')
> >     for chan = 1:length(chans)
> >         try
> >             [EEG.chanlocs(chan).labels, EEG.chanlocs(chan).ref,
> EEG.chanlocs(chan).scale, EEG.chanlocs(chan).unit] =
> strread(hdr.channelinfos{chans(chan)}, '%s%s%s%s', 1, 'delimiter', ',');
> >         catch % Octave compatible code below
> >             str  = hdr.channelinfos{chans(chan)};
> >             [EEG.chanlocs(chan).labels str] = strtok(str, ',');
> >             [EEG.chanlocs(chan).ref        str] = strtok(str, ',');
> >             [EEG.chanlocs(chan).scale      str] = strtok(str, ',');
> >             [EEG.chanlocs(chan).unit       str] = strtok(str, ',');
> >         end;
> >         EEG.chanlocs(chan).labels = char(EEG.chanlocs(chan).labels);
> >         EEG.chanlocs(chan).scale =
> str2double(char(EEG.chanlocs(chan).scale));
> > %             EEG.chanlocs(chan).unit =
> native2unicode(double(char(EEG.chanlocs(chan).scale)), 'UTF-8');
> > %             EEG.chanlocs(chan).datachan = chans(chan);
> >     end
> >     if isempty([EEG.chanlocs.scale])
> >         EEG.chanlocs = rmfield(EEG.chanlocs, 'scale');
> >     end
> > end;
> >
> >
> >
> > I am kind of lost between the repository for the code though so I didn't
> pushed anything.
> >
> > Cheers.
> > --
> > Basile Pinsard
> > PhD candidate,
> > Laboratoire d'Imagerie Biomédicale, UMR S 1146 / UMR 7371, Sorbonne
> Universités, UPMC, INSERM, CNRS
> > Brain-Cognition-Behaviour Doctoral School , ED3C, UPMC, Sorbonne
> Universités
> > Biomedical Sciences Doctoral School, Faculty of Medicine, Université de
> Montréal
> > CRIUGM, Université de Montréal
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>


-- 
Basile Pinsard

*PhD candidate, *
Laboratoire d'Imagerie Biomédicale, UMR S 1146 / UMR 7371, Sorbonne
Universités, UPMC, INSERM, CNRS
*Brain-Cognition-Behaviour Doctoral School **, *ED3C*, *UPMC, Sorbonne
Universités
Biomedical Sciences Doctoral School, Faculty of Medicine, Université de
Montréal
CRIUGM, Université de Montréal
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