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| -rw-r--r-- | samples/matlab/s022_fbp_cor.m | 69 | ||||
| -rw-r--r-- | samples/python/s022_fbp_cor.py | 98 |
2 files changed, 167 insertions, 0 deletions
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); diff --git a/samples/python/s022_fbp_cor.py b/samples/python/s022_fbp_cor.py new file mode 100644 index 0000000..eb2f56b --- /dev/null +++ b/samples/python/s022_fbp_cor.py @@ -0,0 +1,98 @@ +# ----------------------------------------------------------------------- +# Copyright: 2010-2016, iMinds-Vision Lab, University of Antwerp +# 2013-2016, CWI, Amsterdam +# +# Contact: astra@uantwerpen.be +# Website: http://www.astra-toolbox.com/ +# +# This file is part of the ASTRA Toolbox. +# +# +# The ASTRA Toolbox is free software: you can redistribute it and/or modify +# it under the terms of the GNU General Public License as published by +# the Free Software Foundation, either version 3 of the License, or +# (at your option) any later version. +# +# The ASTRA Toolbox is distributed in the hope that it will be useful, +# but WITHOUT ANY WARRANTY; without even the implied warranty of +# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +# GNU General Public License for more details. +# +# You should have received a copy of the GNU General Public License +# along with the ASTRA Toolbox. If not, see <http://www.gnu.org/licenses/>. +# +# ----------------------------------------------------------------------- + +import astra +import numpy as np + +cor_shift = 3.6 + +vol_geom = astra.create_vol_geom(256, 256) +proj_geom = astra.create_proj_geom('parallel', 1.0, 256, np.linspace(0,np.pi,180,False)) + +# Projection geometry with shifted center of rotation +# We create this by shifting the detector center V[:,2:4] by a multiple of the detector +# orientation V[:,4:6]. +proj_geom_cor = astra.functions.geom_2vec(proj_geom) +V = proj_geom_cor['Vectors'] +V[:,2:4] = V[:,2:4] + cor_shift * V[:,4:6] + +# As before, create a sinogram from a phantom, using the shifted center of rotation +import scipy.io +P = scipy.io.loadmat('phantom.mat')['phantom256'] + +proj_id_cor = astra.create_projector('cuda',proj_geom_cor,vol_geom) +sinogram_id, sinogram = astra.create_sino(P, proj_id_cor) + +# Change the projection geometry metadata attached to the sinogram to standard geometry, +# and try to do a reconstruction, to show the misalignment artifacts caused by +# the shifted center of rotation +astra.data2d.change_geometry(sinogram_id, proj_geom) + +import pylab +pylab.gray() +pylab.figure(1) +pylab.imshow(P) +pylab.figure(2) +pylab.imshow(sinogram) + +# Create a data object for the reconstruction +rec_id = astra.data2d.create('-vol', vol_geom) + +# Set up the parameters for a reconstruction algorithm using the GPU +cfg = astra.astra_dict('FBP_CUDA') +cfg['ReconstructionDataId'] = rec_id +cfg['ProjectionDataId'] = sinogram_id +alg_id = astra.algorithm.create(cfg) +astra.algorithm.run(alg_id) + +# Get the result +rec = astra.data2d.get(rec_id) +pylab.figure(3) +pylab.imshow(rec) + +astra.algorithm.delete(alg_id) +astra.data2d.delete(rec_id) + +# Now change back to the proper, shifted geometry, and do another reconstruction +astra.data2d.change_geometry(sinogram_id, proj_geom_cor) +rec_id = astra.data2d.create('-vol', vol_geom) +cfg = astra.astra_dict('FBP_CUDA') +cfg['ReconstructionDataId'] = rec_id +cfg['ProjectionDataId'] = sinogram_id +alg_id = astra.algorithm.create(cfg) +astra.algorithm.run(alg_id) + +# Get the result +rec = astra.data2d.get(rec_id) +pylab.figure(4) +pylab.imshow(rec) +pylab.show() + + + +astra.data2d.delete(sinogram_id) +astra.projector.delete(proj_id_cor) +astra.algorithm.delete(alg_id) +astra.data2d.delete(rec_id) |