Hi Tom and Trippers, <div><br></div><div>To add to Jorn's more detailed answer, if you are ever in doubt as to where to find a FT function, which may be hidden in a private directory (and don't know which of the many private directories to search in), then remember that you can always search for functions on the google FT code page, which doesn't hide the private functions!</div>
<div><br></div><div><a href="http://code.google.com/p/fieldtrip/source/browse/">http://code.google.com/p/fieldtrip/source/browse/</a><br></div><div><br></div><div>and after searching for ft_fetch_sens</div><div><a href="http://code.google.com/p/fieldtrip/source/search?q=ft_fetch_sens&origq=ft_fetch_sens&btnG=Search+Trunk">http://code.google.com/p/fieldtrip/source/search?q=ft_fetch_sens&origq=ft_fetch_sens&btnG=Search+Trunk</a><br>
</div><div><br></div><div>Johanna</div><div><br></div><div><br></div><div class="gmail_extra"><br><br><div class="gmail_quote">2012/11/25 Tom Marshall <span dir="ltr"><<a href="mailto:t.marshall@fcdonders.ru.nl" target="_blank">t.marshall@fcdonders.ru.nl</a>></span><br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div text="#000000" bgcolor="#FFFFFF">
Hi Trippers,<br>
<br>
I'm having some difficulty reinterpolating some missing channels in
my ctf275 data. These are 2 channels that were never recorded
because the sensors in question were switched off.<br>
<br>
Luckily, in the documentation for ft_channelrepair I find:<br>
<br>
"<b>For reconstructing channels that are absent in your data</b>,
please define your neighbours by setting cfg.method='template' and
call FT_PREPARE_NEIGHBOURS *without* the data argument: <br>
cfg.neighbours = ft_prepare_neighbours(cfg);<br>
This will include channels that are missing in your in the
neighbour-definition."<br>
<br>
I dutifully define such a neighbours structure:<br>
<br>
<i>cfg=[]</i><i><br>
</i><i>cfg.method='template';</i><i><br>
</i><i>cfg.template='CTF275_neighb.mat';</i><i><br>
</i><i>n=ft_prepare_neighbours(cfg);</i><br>
<br>
This structure of course contains all 275 MEG channels, including
the ones that are missing from my data.<br>
<br>
So I try to reinterpolate:<br>
<i><br>
</i><i>% get the 'full' list of channel names</i><i><br>
</i><i>for i=1:length(n)</i><i><br>
</i><i> allchans{i,:}=n(i).label;</i><i><br>
</i><i>end</i><i><br>
</i><i><br>
</i><i>% find the names of the channels that were not recorded</i><i><br>
</i><i>missingchans=setdiff(allchans,data.label);</i><i><br>
</i><i><br>
</i><i>% repair</i><i><br>
</i><i>cfg=[];</i><i><br>
</i><i>cfg.missingchannel=missingchans;</i><i><br>
</i><i>cfg.neighbours=n;</i><i><br>
</i><i>cfg.method='spline';</i><i><br>
</i><i>data_r=ft_channelrepair(cfg,data);</i><br>
<br>
this fails with:<br>
<br>
<i>??? Error using ==> minus</i><i><br>
</i><i>Matrix dimensions must agree.</i><i><br>
</i><i><br>
</i><i>Error in ==> ft_channelrepair at 279</i><i><br>
</i><i> d = sens.chanpos - repmat(c, numel(sensidx), 1);</i><br>
<br>
length(sensidx) is 301 and length(sens.chanpos) is 273, so the error
makes sense. However at this point I get a bit stuck as 'sens' is
created in line 104-108 by the function 'ft_fetch_sens' which I
can't find! 'help ft_fetch_sens', 'which ft_fetch_sens' and 'edit
ft_fetch_sens' all fail.<br>
<br>
I guess I have several questions all at once:<br>
1) Is it actually possible to reinterpolate MEG channels that were
never recorded - eg because the channels were deactivated when the
acquisition took place? <br>
2) What might be causing the error I'm seeing?<br>
3) Where is ft_fetch_sens?<br>
<br>
Thanks for help with any of the above!<br>
Best,<br>
Tom<span class="HOEnZb"><font color="#888888"><br>
<pre cols="72">--
Tom Marshall, MSc.
Neuronal Oscillations Group, Donders Centre for Cognitive Neuroimaging
tel: <a href="tel:%2B31%280%29243668487" value="+31243668487" target="_blank">+31(0)243668487</a>
email: <a href="mailto:t.marshall@fcdonders.ru.nl" target="_blank">t.marshall@fcdonders.ru.nl</a>
postal: PO Box 9101, 6500HB, Nijmegen, The Netherlands
visiting: Kapittelweg 29, 6525EN, Nijmegen, The Netherlands</pre>
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