def _forwardproject_block_(projections, volume, proj_geom, vol_geom, operation = '+'):
"""
Use this internal function to compute backprojection of a single block of data.
"""
try:
if (operation == '+'):
projections_ = projections
elif (operation == '*') | (operation == '/'):
projections_ = numpy.zeros_like(projections)
else: ValueError('Unknown operation type!')
sin_id = astra.data3d.link('-sino', proj_geom, projections_)
vol_id = astra.data3d.link('-vol', vol_geom, volume)
projector_id = astra.create_projector('cuda3d', proj_geom, vol_geom)
asex.accumulate_FP(projector_id, vol_id, sin_id)
if (operation == '*'):
projections *= projections_
elif (operation == '/'):
projections_[projections_ < 1e-10] = numpy.inf
projections /= projections_
except:
print("ASTRA error:", sys.exc_info())
finally:
astra.algorithm.delete(projector_id)
astra.data3d.delete(sin_id)
astra.data3d.delete(vol_id)
def _forwardproject_block_add_(projections,
volume,
proj_geom,
vol_geom,
negative=False):
"""
Additive forwardprojection of a single block.
Use negative = True if you want subtraction instead of addition.
"""
try:
# We are goint to negate the projections block and not the whole volume:
if negative:
projections *= -1
# If volume is a memmap - create a temporary copy in RAM
if isinstance(volume, numpy.memmap):
vol_temp = numpy.ascontiguousarray(volume)
vol_id = astra.data3d.link('-vol', vol_geom, vol_temp)
else:
vol_id = astra.data3d.link('-vol', vol_geom, volume)
sin_id = astra.data3d.link('-sino', proj_geom, projections)
projector_id = astra.create_projector('cuda3d', proj_geom, vol_geom)
# Project!
asex.accumulate_FP(projector_id, vol_id, sin_id)
# Negate second time:
if negative:
projections *= -1
except:
# Always try to delete data3d:
try:
astra.algorithm.delete(projector_id)
astra.data3d.delete(sin_id)
astra.data3d.delete(vol_id)
finally:
info = sys.exc_info()
traceback.print_exception(*info)
astra.algorithm.delete(projector_id)
astra.data3d.delete(sin_id)
astra.data3d.delete(vol_id)
def _forwardproject_block(self, proj_data, proj_geom, vol_data, vol_geom):
'''
Forwardproject a single block of data
'''
try:
sin_id = astra.data3d.link('-sino', proj_geom, proj_data)
vol_id = astra.data3d.link('-vol', vol_geom, vol_data)
projector_id = astra.create_projector('cuda3d', proj_geom,
vol_geom)
#print('**proj_data', proj_data.sum())
asex.accumulate_FP(projector_id, vol_id, sin_id)
#print('**proj_data', proj_data.sum())
except:
print("ASTRA error:", sys.exc_info())
finally:
astra.data3d.delete(sin_id)
astra.data3d.delete(vol_id)
astra.projector.delete(projector_id)
return proj_data