<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2//EN">
<HTML>
<HEAD>
<META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=iso-8859-1">
<META NAME="Generator" CONTENT="MS Exchange Server version 6.5.7651.53">
<TITLE>Creating Leadfield using BEM</TITLE>
</HEAD>
<BODY>
<!-- Converted from text/plain format -->
<P><FONT SIZE=2>Dear Fieldtrippers,<BR>
<BR>
I am trying to compute a beamform localisation using a BEM-model of the head. When I call ft_sourceanalysis i receive to following error.<BR>
<BR>
??? Error using ==> svd<BR>
Input to SVD must not contain NaN or Inf.<BR>
<BR>
Error in ==> beamformer_lcmv>pinv at 367<BR>
[U,S,V] = svd(A,0);<BR>
<BR>
Error in ==> beamformer_lcmv at 255<BR>
filt = pinv(lf' * invCy * lf) * lf' * invCy; % van Veen eqn. 23, use PINV/SVD to cover rank deficient leadfield<BR>
<BR>
Error in ==> ft_sourceanalysis at 818<BR>
dip(i) = beamformer_lcmv(grid, sens, vol, squeeze(avg(i,:,:)), squeeze(Cy(i,:,:)), optarg{:});<BR>
<BR>
<BR>
I noticed that my leadfieldgrid containend NaN values. I think this could be the cause, but I don't know how to fix this problem. Does anyone have an idea?<BR>
<BR>
My script is as follows<BR>
<BR>
vol=ft_read_vol('standard_vol.mat')<BR>
elec=ft_read_sens('standard_1005.elc') % reading the 1005 systeem because the experiment used of 32 electrodes<BR>
<BR>
cfg=[]<BR>
cfg.showlabels= 'yes'<BR>
cfg.layout='EEG1010.lay'<BR>
cfg.interactive= 'yes'<BR>
<BR>
<BR>
% Reref<BR>
load (['C:\Users\Brian\Documents\MATLAB\AnalysisM\differencewave0' Subject])<BR>
<BR>
cfg=[]<BR>
cfg.reref='yes' % referring the<BR>
cfg.refchannel= 'all' % commonaverage reference<BR>
diff=ft_preprocessing(cfg,diffwav)<BR>
<BR>
%% Creating LEADFIELD<BR>
cfg = [];<BR>
cfg.elec = elec;<BR>
cfg.vol = vol;<BR>
cfg.reducerank = 3;<BR>
cfg.channel = 'all';<BR>
cfg.grid.resolution = 10; % use a 3-D grid with a 10 mm resolution<BR>
[grid] = ft_prepare_leadfield(cfg);<BR>
<BR>
save('AnalysisM\Grid_10mm', 'grid')<BR>
<BR>
%%<BR>
cfg = [];<BR>
cfg.covariance = 'yes';<BR>
cfg.covariancewindow = [0 .75];<BR>
cfg.removemean = 'no';<BR>
tlckavgpst = ft_timelockanalysis(cfg, diff);<BR>
cfg.covariancewindow = [-0.25 0];<BR>
tlckavgpre = ft_timelockanalysis(cfg, diff);<BR>
<BR>
<BR>
%%<BR>
cfg = [];<BR>
cfg.method = 'lcmv';<BR>
cfg.vol = vol;<BR>
cfg.elec = elec<BR>
cfg.lambda = '5%'; <BR>
sourcepst = ft_sourceanalysis(cfg, tlckavgpst);<BR>
sourcepre = ft_sourceanalysis(cfg, tlckavgpre);<BR>
<BR>
sourcepst.avg.nai = sourcepst.avg.pow./sourcepre.avg.pow;<BR>
<BR>
<BR>
Thanks in advance!<BR>
<BR>
Brian<BR>
<BR>
<BR>
</FONT>
</P>
<br clear=all>
<html>
<body>
<p style="font-size:13px;font-family:arial;">
Het UMC St Radboud staat geregistreerd bij de Kamer van Koophandel in het handelsregister onder nummer 41055629.<BR> The Radboud University Nijmegen Medical Centre is listed in the Commercial Register of the Chamber of Commerce under file number 41055629.<BR>
</p>
</body>
</html>
</BODY>
</HTML>