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import astra
import numpy as np
def convert_geometry_to_astra(volume_geometry, sinogram_geometry):
'''Set up ASTRA Volume and projection geometry, not stored
:param volume_geometry: ccpi.framework.ImageGeometry
:param sinogram_geometry: ccpi.framework.AcquisitionGeometry
:returns ASTRA volume and sinogram geometry'''
# determine if the geometry is 2D or 3D
horiz = sinogram_geometry.pixel_num_h
vert = sinogram_geometry.pixel_num_v
if vert >= 1:
dimension = '3D'
elif vert == 0:
dimension = '2D'
else:
raise ValueError('Number of pixels at detector on the vertical axis must be >= 0. Got {}'.format(vert))
if dimension == '2D':
vol_geom = astra.create_vol_geom(volume_geometry.voxel_num_x,
volume_geometry.voxel_num_y,
volume_geometry.get_min_x(),
volume_geometry.get_max_x(),
volume_geometry.get_min_y(),
volume_geometry.get_max_y())
if sinogram_geometry.geom_type == 'parallel':
proj_geom = astra.create_proj_geom('parallel',
sinogram_geometry.pixel_size_h,
sinogram_geometry.pixel_num_h,
sinogram_geometry.angles)
elif sinogram_geometry.geom_type == 'cone':
proj_geom = astra.create_proj_geom('fanflat',
sinogram_geometry.pixel_size_h,
sinogram_geometry.pixel_num_h,
sinogram_geometry.angles,
np.abs(sinogram_geometry.dist_source_center),
np.abs(sinogram_geometry.dist_center_detector))
else:
NotImplemented
elif dimension == '3D':
vol_geom = astra.create_vol_geom(volume_geometry.voxel_num_x,
volume_geometry.voxel_num_y,
volume_geometry.voxel_num_z,
volume_geometry.get_min_x(),
volume_geometry.get_max_x(),
volume_geometry.get_min_y(),
volume_geometry.get_max_y(),
volume_geometry.get_min_z(),
volume_geometry.get_max_z())
if sinogram_geometry.geom_type == 'parallel':
proj_geom = astra.create_proj_geom('parallel3d',
sinogram_geometry.pixel_size_h,
sinogram_geometry.pixel_size_v,
sinogram_geometry.pixel_num_v,
sinogram_geometry.pixel_num_h,
sinogram_geometry.angles)
elif sinogram_geometry.geom_type == 'cone':
proj_geom = astra.create_proj_geom('cone',
sinogram_geometry.pixel_size_h,
sinogram_geometry.pixel_size_v,
sinogram_geometry.pixel_num_v,
sinogram_geometry.pixel_num_h,
sinogram_geometry.angles,
np.abs(sinogram_geometry.dist_source_center),
np.abs(sinogram_geometry.dist_center_detector))
else:
NotImplemented
else:
NotImplemented
return vol_geom, proj_geom
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