From 84da1d5e27abadf28e97695e88494c58bf1c2697 Mon Sep 17 00:00:00 2001 From: Willem Jan Palenstijn Date: Tue, 9 Jan 2018 14:09:23 +0100 Subject: Add sample script using parallel_vec --- samples/matlab/s022_fbp_cor.m | 69 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 69 insertions(+) create mode 100644 samples/matlab/s022_fbp_cor.m (limited to 'samples/matlab') diff --git a/samples/matlab/s022_fbp_cor.m b/samples/matlab/s022_fbp_cor.m new file mode 100644 index 0000000..b33d5ce --- /dev/null +++ b/samples/matlab/s022_fbp_cor.m @@ -0,0 +1,69 @@ +% ----------------------------------------------------------------------- +% This file is part of the ASTRA Toolbox +% +% Copyright: 2010-2016, iMinds-Vision Lab, University of Antwerp +% 2014-2016, CWI, Amsterdam +% License: Open Source under GPLv3 +% Contact: astra@uantwerpen.be +% Website: http://www.astra-toolbox.com/ +% ----------------------------------------------------------------------- + +cor_shift = 3.6; + +vol_geom = astra_create_vol_geom(256, 256); +proj_geom = astra_create_proj_geom('parallel', 1.0, 256, linspace2(0,pi,180)); + +% Projection geometry with shifted center of rotation +% We create this by shifting the detector center V(:,3:4) by a multiple of the detector +% orientation V(:,5:6). +proj_geom_cor = astra_geom_2vec(proj_geom); +proj_geom_cor.Vectors(:,3:4) = proj_geom_cor.Vectors(:,3:4) + cor_shift * proj_geom_cor.Vectors(:,5:6); + +% As before, create a sinogram from a phantom, using the shifted center of rotation +P = phantom(256); +[sinogram_id, sinogram] = astra_create_sino_gpu(P, proj_geom_cor, vol_geom); +figure(1); imshow(P, []); +figure(2); imshow(sinogram, []); + +astra_mex_data2d('delete', sinogram_id); + +% We now re-create the sinogram data object as we would do when loading +% an external sinogram, using a standard geometry, and try to do a reconstruction, +% to show the misalignment artifacts caused by the shifted center of rotation +sinogram_id = astra_mex_data2d('create', '-sino', proj_geom, 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('FBP_CUDA'); +cfg.ReconstructionDataId = rec_id; +cfg.ProjectionDataId = sinogram_id; +alg_id = astra_mex_algorithm('create', cfg); +astra_mex_algorithm('run', alg_id); + +% Get the result +rec = astra_mex_data2d('get', rec_id); +figure(3); imshow(rec, []); + +astra_mex_algorithm('delete', alg_id); +astra_mex_data2d('delete', rec_id); + +% Now change back to the proper, shifted geometry, and do another reconstruction +astra_mex_data2d('change_geometry', sinogram_id, proj_geom_cor); +rec_id = astra_mex_data2d('create', '-vol', vol_geom); + +cfg = astra_struct('FBP_CUDA'); +cfg.ReconstructionDataId = rec_id; +cfg.ProjectionDataId = sinogram_id; +alg_id = astra_mex_algorithm('create', cfg); +astra_mex_algorithm('run', alg_id); + +% Get the result +rec = astra_mex_data2d('get', rec_id); +figure(4); imshow(rec, []); + + +astra_mex_algorithm('delete', alg_id); +astra_mex_data2d('delete', rec_id); +astra_mex_data2d('delete', sinogram_id); -- cgit v1.2.3