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# -----------------------------------------------------------------------
# Copyright: 2010-2021, imec Vision Lab, University of Antwerp
# 2013-2021, CWI, Amsterdam
#
# Contact: astra@astra-toolbox.com
# 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
vol_geom = astra.create_vol_geom(256, 256)
proj_geom = astra.create_proj_geom('parallel', 3.0, 128, np.linspace(0,np.pi,180,False))
import scipy.io
P = scipy.io.loadmat('phantom.mat')['phantom256']
# Because the astra.create_sino method does not have support for
# all possible algorithm options, we manually create a sinogram
phantom_id = astra.data2d.create('-vol', vol_geom, P)
sinogram_id = astra.data2d.create('-sino', proj_geom)
cfg = astra.astra_dict('FP_CUDA')
cfg['VolumeDataId'] = phantom_id
cfg['ProjectionDataId'] = sinogram_id
# Set up 3 rays per detector element
cfg['option'] = {}
cfg['option']['DetectorSuperSampling'] = 3
alg_id = astra.algorithm.create(cfg)
astra.algorithm.run(alg_id)
astra.algorithm.delete(alg_id)
astra.data2d.delete(phantom_id)
sinogram3 = astra.data2d.get(sinogram_id)
import pylab
pylab.gray()
pylab.figure(1)
pylab.imshow(P)
pylab.figure(2)
pylab.imshow(sinogram3)
# Create a reconstruction, also using supersampling
rec_id = astra.data2d.create('-vol', vol_geom)
cfg = astra.astra_dict('SIRT_CUDA')
cfg['ReconstructionDataId'] = rec_id
cfg['ProjectionDataId'] = sinogram_id
# Set up 3 rays per detector element
cfg['option'] = {}
cfg['option']['DetectorSuperSampling'] = 3
# There is also an option for supersampling during the backprojection step.
# This should be used if your detector pixels are smaller than the voxels.
# Set up 2 rays per image pixel dimension, for 4 rays total per image pixel.
# cfg['option']['PixelSuperSampling'] = 2
alg_id = astra.algorithm.create(cfg)
astra.algorithm.run(alg_id, 150)
astra.algorithm.delete(alg_id)
rec = astra.data2d.get(rec_id)
pylab.figure(3)
pylab.imshow(rec)
pylab.show()
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