EIDORS: Electrical Impedance Tomography and Diffuse Optical Tomography Reconstruction Software

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Build circular 2D models with distmesh

The function function dm_2d_circ_pt_elecs allows building of 2d circular EIDORS models with distmesh and provides a way to refine points.

Create 3 electrode basic model

% Simple model with three electrodes $Id: circ_2d_model01.m 5765 2018-05-20 11:55:14Z aadler $
elec_pts{1} = [1,0]; % Point electrode
elec_pts{2} = [0,1;sin(0.2),cos(0.2)]; % Complete electrode between points
elec_pts{3} = [0.5,0.5]; % Point internal electode

fmdl= dm_2d_circ_pt_elecs( elec_pts, [], [0.10,10,0.05] );
subplot(221); show_fem(fmdl); axis equal

fmdl= dm_2d_circ_pt_elecs( elec_pts, [], [0.10,10,0.02] );
subplot(222); show_fem(fmdl); axis equal

print_convert circ_2d_model01.png '-density 125'

Figure: Circular model generated by dm_2d_circ_pt_elecs, for two different mesh densities

Create regular electrode basic model

% Simple model with three electrodes $Id: circ_2d_model01.m 5765 2018-05-20 11:55:14Z aadler $
elec_pts{1} = [1,0]; % Point electrode
elec_pts{2} = [0,1;sin(0.2),cos(0.2)]; % Complete electrode between points
elec_pts{3} = [0.5,0.5]; % Point internal electode

fmdl= dm_2d_circ_pt_elecs( elec_pts, [], [0.10,10,0.05] );
subplot(221); show_fem(fmdl); axis equal

fmdl= dm_2d_circ_pt_elecs( elec_pts, [], [0.10,10,0.02] );
subplot(222); show_fem(fmdl); axis equal

print_convert circ_2d_model01.png '-density 125'

Figure: Circular model generated by dm_2d_circ_pt_elecs, for two different mesh densities

Exploring Parameter Choices For Distmesh models

% Simple model with three electrodes $Id: circ_2d_model03.m 2768 2011-07-14 16:43:03Z bgrychtol $
elec_pts= {};
n_elecs= 8;
elec_width= 0.1;

hw= elec_width/2;
th = linspace(0,2*pi,n_elecs+1); th(end)=[];
for i=1:n_elecs;
   ti = th(i) + [hw;-hw];
   elec_pts{i} = [sin(ti),cos(ti)];
end

params = [0.10,10,0.05;
          0.10,10,0.02;
          0.10,10,0.005;
          0.10,30,0.005;
          0.10,50,0.005;
          0.05,10,0.02;
          0.03,10,0.02;
          0.02,10,0.02;
          0.10,10,0.001;
          0.05,10,0.001 ];

clf
for i=1:5; for j=0:1
   param= params(i+5*j,:);
   fmdl= dm_2d_circ_pt_elecs( elec_pts, [], param );

   axes('position',[0.05+0.49*j,(i-1)*0.17+0.10,0.45,0.13]);
   show_fem(fmdl);
   axis([0,1.05,-0.2,0.2]);
   text(0,0.25,sprintf('Params=[%4.2f,%2d,%5.3f]. #Elems= %d ', param, size(fmdl.elems,1)));
   if i>1; set(gca,'XTickLabel',[]); end
end; end

print_convert circ_2d_model03.png '-density 200'

Figure: Eight electrode model for various parameter choices indicated.