EIDORS: Electrical Impedance Tomography and Diffuse Optical Tomography Reconstruction Software

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GREIT Reconstruction for multiple electrode layers

Simulation model

% $Id: mk_GREIT_mat_2layer01.m 2554 2011-04-28 19:14:20Z aadler $
n_elecs = 8;
layers = [0.8,1.2];
stim =  mk_stim_patterns(n_elecs*length(layers),1,[0,1],[0,1], ...
             {'no_meas_current'}, 1);

extra={'lungs','solid lungs = sphere(0.9,0.1,1.65;0.3) or sphere(-0.9,0.1,1;0.3);'};
[fmdl,midx] = ng_mk_ellip_models([2, 2,1.4,0.2] ,[n_elecs,layers],[0.1], extra);
fmdl.stimulation =  stim;

img = mk_image(fmdl,1); % Homogeneous background
vh = fwd_solve(img);
img.elem_data(midx{2}) = 0.5; % Lung regions
vi = fwd_solve(img);

show_fem(img,[0,1]); view(0,70);
print_convert mk_GREIT_mat_2layer01a.png '-density 60'
view(0,10);
print_convert mk_GREIT_mat_2layer01b.png '-density 60'

Figure: Simulation of data on an elliptical model with lung shaped contrasting regions

Calculate GREIT reconstruction matrix

% $Id: mk_GREIT_mat_2layer02.m 4341 2013-09-24 16:08:49Z aadler $
opt.imgsz = [32 32];
opt.distr = 3; % non-random, uniform
opt.Nsim = 1000;
opt.target_size = 0.05; % Target size (frac of medium)
opt.noise_figure = 1.0; % Recommended NF=0.5;
% opt.target_layer = 1.0; % Default is in the centre

fmdl = ng_mk_ellip_models([2, 2,1.4,0.2] ,[n_elecs,layers],[0.1]);
fmdl.stimulation =  stim;
fmdl = mdl_normalize(fmdl, 0);
img = mk_image(fmdl,1);

imdl = mk_GREIT_model(img, 0.25, [], opt);

show_fem(fmdl); view(0,70);

print_convert mk_GREIT_mat_2layer02a.png '-density 60'

Figure: Simulation of data on an elliptical model with lung shaped contrasting regions

Reconstruct Images

% $Id: mk_GREIT_mat_2layer03.m 2553 2011-04-28 19:03:58Z aadler $

rimg = inv_solve(imdl,vh,vi); %Reconstruct
rimg.calc_colours.ref_level=0;

show_fem(rimg); axis square;

print_convert mk_GREIT_mat_2layer03a.png '-density 60'

Figure: Reconstructed images