EIDORS: Electrical Impedance Tomography and Diffuse Optical Tomography Reconstruction Software

Hosted by

Viewing surface and depth voltages

Create a simple 3D model (electrodes at 170° and 190°

% Create fwd model
el_pos = [190,0.5;170,0.5];
fmdl= ng_mk_cyl_models(1,el_pos,[0.05,0,0.05]); 

% Solve fwd model
fmdl.stimulation(1).stim_pattern = [1;-1];
fmdl.stimulation(1).meas_pattern = [1,-1]; % dummy
img = mk_image(fmdl,1);
img.fwd_solve.get_all_meas = 1;
vh=fwd_solve(img);

clf;show_fem(fmdl);
print_convert view_3D_surf01a.png '-density 75'

Figure: Cylinder with electrodes at 170° and 190°

Show voltage on surface

imgv = rmfield(img,'elem_data');
imgv.node_data = vh.volt(:,1);

colours = calc_colours(imgv,[]);
patch('Faces',fmdl.boundary,'Vertices',fmdl.nodes, 'facecolor','interp', ...
      'facevertexcdata',colours,'CDataMapping','direct'); 

print_convert view_3D_surf02a.jpg '-density 75'
view(0,0)
print_convert view_3D_surf02b.jpg '-density 75'

Figure: Two views of surface voltage on cylinder

Show vertical slices (internal)

% Four cut planes
cut_planes = -[0.6;0.7;0.8;0.9];
imgv.calc_colours.backgnd = 0.9*[1,1,1];
show_slices(imgv,cut_planes*[inf,1,inf]);
print_convert view_3D_surf03a.png '-density 150'

Figure: Vertical slices of internal voltage at 0.6, 0.7, 0.8, 0.9

Adding contrasts to adjust surface voltages

% Create fwd model
el_pos = [190,0.5;170,0.5];
extra = {'cube',['solid cube = orthobrick(-0.2 ,-0.97,0.6;0.2,0,0.7) or ' ...
                              'orthobrick( 0.15,-0.97,0.4;0.2,0,0.7) ;']};
fmdl= ng_mk_cyl_models([1,1,.05],el_pos,[0.05,0,0.05],extra); 

% Solve fwd model
fmdl.stimulation(1).stim_pattern = [1;-1];
fmdl.stimulation(1).meas_pattern = [1,-1]; % dummy
img = mk_image(fmdl,1);
img.elem_data(fmdl.mat_idx{2}) = 10000;
img.fwd_solve.get_all_meas = 1;
vh=fwd_solve(img);

clf;show_fem(img);
print_convert view_3D_surf04a.jpg '-density 75'
view(0,0);
print_convert view_3D_surf04b.jpg '-density 75'

Figure: Cylinder model with contrasting region (higher mesh density to see details)

imgv = rmfield(img,'elem_data');
imgv.node_data = vh.volt(:,1);

imgv.calc_colours.clim = 0.3; % Colour limits
colours = calc_colours(imgv,[]);
show_fem(fmdl);
patch('Faces',fmdl.boundary,'Vertices',fmdl.nodes, 'facecolor','interp', ...
      'facevertexcdata',colours,'CDataMapping','direct'); 

view(0,0)
print_convert view_3D_surf05b.jpg

Figure: Two views of surface voltage on cylinder