1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
|
% -----------------------------------------------------------------------
% This file is part of the ASTRA Toolbox
%
% Copyright: 2010-2015, iMinds-Vision Lab, University of Antwerp
% 2014-2015, CWI, Amsterdam
% License: Open Source under GPLv3
% Contact: astra@uantwerpen.be
% Website: http://sf.net/projects/astra-toolbox
% -----------------------------------------------------------------------
vol_geom = astra_create_vol_geom(256, 256);
proj_geom = astra_create_proj_geom('parallel', 1.0, 384, linspace2(0,pi,180));
% As before, create a sinogram from a phantom
P = phantom(256);
[sinogram_id, sinogram] = astra_create_sino_gpu(P, proj_geom, vol_geom);
figure(1); imshow(P, []);
figure(2); imshow(sinogram, []);
% Create a data object for the reconstruction
rec_id = astra_mex_data2d('create', '-vol', vol_geom);
% Set up the parameters for a reconstruction algorithm using the GPU
cfg = astra_struct('SIRT_CUDA');
cfg.ReconstructionDataId = rec_id;
cfg.ProjectionDataId = sinogram_id;
% Create the algorithm object from the configuration structure
alg_id = astra_mex_algorithm('create', cfg);
% Run 1500 iterations of the algorithm one at a time, keeping track of errors
nIters = 1500;
phantom_error = zeros(1, nIters);
residual_error = zeros(1, nIters);
for i = 1:nIters;
% Run a single iteration
astra_mex_algorithm('iterate', alg_id, 1);
residual_error(i) = astra_mex_algorithm('get_res_norm', alg_id);
rec = astra_mex_data2d('get', rec_id);
phantom_error(i) = sqrt(sumsqr(rec - P));
end
% Get the result
rec = astra_mex_data2d('get', rec_id);
figure(3); imshow(rec, []);
figure(4); plot(residual_error)
figure(5); plot(phantom_error)
% Clean up.
astra_mex_algorithm('delete', alg_id);
astra_mex_data2d('delete', rec_id);
astra_mex_data2d('delete', sinogram_id);
|
