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GREIT Reconstruction Matrix

The AUSPEX Software is an EIT evaluate and analysis software from Carefusion. AUSPEX is designed to analyse data collected from the Geo II MF EIT system. It uses a reconstruction algorithm based on Sheffield backprojection.

To replace this algorithm with GREIT algorithm, one needs to replace the file ReconstructionMatrixF.mat with another one calculated by this tutorial.

Circular GREIT model

n_elecs = 16;
fmdl = ng_mk_cyl_models([1 1 0.1] ,[n_elecs,.5],[0.05]);
% NOTE: The 'rotate_meas' is essential here.
fmdl.stimulation =  mk_stim_patterns(n_elecs,1,[0,1],[0,1],{'rotate_meas','no_meas_current'}, 1);
fmdl = mdl_normalize(fmdl, 1); %MUST FOR AUSPEX

opt.imgsz = [32 32];
opt.distr = 3; 
opt.noise_figure = 0.5; 
imdl = mk_GREIT_model(fmdl, 0.20, [], opt);

% DESTINATION AUSPEX MODEL
cmdl = mk_common_gridmdl('b2d','backproj');
cmdl = rmfield(cmdl.fwd_model,'coarse2fine');
% MODEL GEOMETRIES MUST MATCH
f2c  = mk_coarse_fine_mapping(cmdl, imdl.rec_model);

RM = f2c*imdl.solve_use_matrix.RM(1:size(f2c,2),:);

ReconstrMatrix= - ( RM(1:2:end,:) + RM(2:2:end,:) )';
save ReconstrMatrixGREITc ReconstrMatrix -V6;

Adult human GREIT model

n_elecs = 16;
   fmdl= mk_library_model('adult_male_16el');
   fmdl.electrode = fmdl.electrode([9:16,1:8]);
   fmdl.electrode = fmdl.electrode([1,16:-1:2]);
   fmdl.stimulation =  mk_stim_patterns(n_elecs,1,[0,1],[0,1],{'rotate_meas','no_meas_current'}, 1);

   fmdl = mdl_normalize(fmdl, 1);
   img = mk_image(fmdl,1); % Homogeneous background

   opt.imgsz = [32 32];
   opt.distr = 3; 
   opt.noise_figure = 0.5; 
   imdl = mk_GREIT_model(fmdl, 0.25, [], opt);

% MODEL
fmdl = imdl.rec_model;
fmdl.nodes = fmdl.nodes/max(fmdl.nodes(:))*1.1*[1,0;0,-1];
cmdl = mk_common_gridmdl('b2d','backproj');
cmdl = rmfield(cmdl.fwd_model,'coarse2fine');
f2c  = mk_coarse_fine_mapping(cmdl, fmdl);

RM = f2c*imdl.solve_use_matrix.RM(1:size(f2c,2),:);

ReconstrMatrix= - ( RM(1:2:end,:) + RM(2:2:end,:) )';
save ReconstrMatrixGREITt ReconstrMatrix -V6;

Test Simulations

imdl = mk_common_model('c2c2',16);
imdl.fwd_model.stimulation =  ...
     mk_stim_patterns(16,1,[0,1],[0,1],{'rotate_meas','no_meas_current'},1);
img = mk_image(imdl);     vh = fwd_solve( img );
img.elem_data(290) = 1.1; vi = fwd_solve( img );

clf;subplot(221);
show_fem(img); title('Test Object');
print_convert GREIT_AUSPEX03a.png


Figure: Simulation with target to test AUSPEX matrix

Test of GREIT/AUSPEX matrices

s=1;
fnames = {'ReconstrMatrixGREITc.mat','ReconstrMatrixGREITt.mat'};
for i=1:length(fnames);
   load(fnames{i});
   imdl = mk_common_gridmdl('b2d',ReconstrMatrix');

   imgr= inv_solve(imdl, vh, vi);
   subplot(2,2,s+0); show_fem(imgr);
   title('Test Object Reconstruction');
   
   imgr.elem_data = mean(ReconstrMatrix==0)';
   subplot(2,2,s+1); show_fem(imgr);
   title('Domain Boundary');
s=s+2;end
print_convert GREIT_AUSPEX04a.png


Figure: LeftReconstructions. RightReconstruction Domain

Last Modified: $Date: 2017-02-28 13:12:08 -0500 (Tue, 28 Feb 2017) $ by $Author: aadler $