Eidors-logo    

EIDORS: Electrical Impedance Tomography and Diffuse Optical Tomography Reconstruction Software

EIDORS (mirror)
Main
Documentation
Tutorials
− Image Reconst
− Data Structures
− Applications
− FEM Modelling
− GREIT
− Old tutorials
Workshop
Download
Contrib Data
GREIT
Browse Docs
Browse SVN

News
Mailing list
(archive)
FAQ
Developer
                       

 

Hosted by
SourceForge.net Logo

 

Images of the Pont Péan region

The Pont Péan was an important silver mine before it flooded in April 1, 1904. Historical information is explained can be found at fr.Wikipedia.org and galene.fr. Due to the regular geophysical geometries of the site, and the large conductivity contrast of the ore with the surrounding rock, it represents an excellent test site for geophysical EIT measurements.

The data are available here. They were measured by a team of geophysical researchers at Université Rennes 1 over the period 2000−2011.

Create 3D FEM model of the terrain

% Load data and positions
gps = load('Mine_20FEV2004.gps');
data= load('Mine_20FEV2004_LI.tomel');

% Forward Model
shape_str = ['solid top    = plane(0,0,0;0,1,0);\n' ...
             'solid mainobj= top and orthobrick(-100,-200,-100;425,10,100) -maxh=20.0;\n'];
elec_pos = gps(:,2:4); e0 = elec_pos(:,1)*0;
elec_pos = [  elec_pos, e0, e0+1, e0 ]; 
elec_shape=[0.5,.5,.5];
elec_obj = 'top';
fmdl = ng_mk_gen_models(shape_str, elec_pos, elec_shape, elec_obj);

fmdl.stimulation = stim_meas_list( data(:,3:6) - 40100);

show_fem(fmdl);


Figure: Forward model

Create 2½D inverse model

%Reconstruction model
[cmdl]= mk_grid_model([], 2.5+[-50,-20,0:10:320,340,370], ...
                             -[0:2.5:10, 15:5:25,30:10:80,100,120]);
c2f = mk_coarse_fine_mapping( fmdl, cmdl);

fmdl.coarse2fine = c2f;
imdl= eidors_obj('inv_model','test');
imdl.fwd_model= fmdl;
imdl.rec_model= cmdl;
   imdl.reconst_type = 'difference';
   imdl.RtR_prior = @prior_laplace;
   imdl.solve = @inv_solve_diff_GN_one_step;
   imdl.hyperparameter.value = 0.3;
   imdl.fwd_model.normalize_measurements = 1;
   imdl.jacobian_bkgnd.value = 0.03;

hold on
show_fem(cmdl);
view([0 -0.2 1])
hold off
print_convert pont_pean01a.png

Reconstruct the data

% Difference image vs simulated data
vr = data(:,9);
img = mk_image( imdl );
vh = fwd_solve(img); vh = vh.meas;

imgr = inv_solve(imdl, vh, vr);

show_fem(imgr);
print_convert pont_pean3a.png


Figure: Reconstruction (2½D) using a one step GN algorithm

Comparison to Apparent Resistivity

Figure: Apparent resistivity plot (not using EIDORS)

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