added test script for fieldtrip/website#832

fieldtrip · Jan 21, 2025 · 797eba3 · 797eba3
1 parent cce618f
commit 797eba3
Showing 1 changed file with 75 additions and 0 deletions.
diff --git a/test/test_example_sourcerecon_meeg.m b/test/test_example_sourcerecon_meeg.m
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+% function test_example_sourcerecon_meeg
+
+% MEM 2gb
+% WALLTIME 00:10:00
+% DATA none
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+% create a set of electrodes, randomly placed on the sphere
+elec = [];
+elec.elecpos = randn(32,3);
+dum = sqrt(sum(elec.elecpos.^2,2));                  % compute the distance to the origin
+elec.elecpos = elec.elecpos ./ [dum dum dum] * 0.10; % scale them to a 0.1 meter sphere
+for i=1:32
+  elec.label{i} = sprintf('eeg%03d', i);
+end
+
+% create a concentric 3-sphere volume conductor for the EEG, the radius is the same as for the electrodes
+headmodel_eeg   = [];
+headmodel_eeg.r = [0.088 0.092 0.100]; % radii of spheres
+headmodel_eeg.c = [1 1/80 1];          % conductivity
+headmodel_eeg.o = [0 0 0];             % center of sphere
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+% create a set of magnetometers, randomly placed around the sphere
+grad = [];
+grad.coilpos = randn(64,3);
+dum = sqrt(sum(grad.coilpos.^2,2));
+grad.coilpos = grad.coilpos ./ [dum dum dum] * 0.12; % scale them to a 0.12 meter sphere, shifted outward from the head surface
+grad.coilori = grad.coilpos ./ [dum dum dum];        % unit length
+for i=1:64
+  grad.label{i} = sprintf('meg%03d', i);
+end
+grad.tra = eye(64,64);
+
+% create a single-sphere volume conductor for the MEG
+headmodel_meg   = [];
+headmodel_meg.r = 0.1;             % radius of sphere
+headmodel_meg.c = 1;                % conductivity
+headmodel_meg.o = [0 0 0];          % center of sphere
+
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+% combine the EEG and MEG sensor definitions and volume conductor models
+% and do a forward computation
+combined_headmodel = {headmodel_eeg, headmodel_meg};
+combined_sens = {elec, grad};
+
+pos = [0 0 0.8];
+mom = [1 0 0]';
+
+[combined_headmodel{1}, combined_sens{1}] = ft_prepare_vol_sens(combined_headmodel{1}, combined_sens{1});
+[combined_headmodel{2}, combined_sens{2}] = ft_prepare_vol_sens(combined_headmodel{2}, combined_sens{2});
+leadfield  = ft_compute_leadfield(pos, combined_sens, combined_headmodel);
+
+assert(size(leadfield,1)==96);
+assert(size(leadfield,2)==3);
+
+eeg = leadfield(1:32,:)*mom;
+meg = leadfield(33:end,:)*mom;
+
+figure; plot(eeg); title('eeg');
+figure; plot(meg); title('meg');
+
+ft_senstype(combined_sens)
+ft_headmodeltype(combined_headmodel)
+
+figure
+ft_plot_topo3d(elec.elecpos, eeg)
+ft_plot_sens(elec, 'axes', true)
+ft_plot_headmodel(headmodel_eeg, 'facecolor', 'skin', 'facealpha', 0.5)
+
+figure
+ft_plot_topo3d(grad.coilpos, meg)
+ft_plot_sens(grad, 'axes', true)
+ft_plot_headmodel(headmodel_meg, 'facecolor', 'skin', 'facealpha', 0.5)
+