diff options
Diffstat (limited to 'python/astra/functions.py')
-rw-r--r-- | python/astra/functions.py | 56 |
1 files changed, 55 insertions, 1 deletions
diff --git a/python/astra/functions.py b/python/astra/functions.py index 7277de5..b3a470d 100644 --- a/python/astra/functions.py +++ b/python/astra/functions.py @@ -172,7 +172,27 @@ def geom_2vec(proj_geom): :param proj_geom: Projection geometry to convert :type proj_geom: :class:`dict` """ - if proj_geom['type'] == 'fanflat': + + if proj_geom['type'] == 'parallel': + angles = proj_geom['ProjectionAngles'] + vectors = np.zeros((len(angles), 6)) + for i in range(len(angles)): + + # source + vectors[i, 0] = np.sin(angles[i]) + vectors[i, 1] = -np.cos(angles[i]) + + # center of detector + vectors[i, 2] = 0 + vectors[i, 3] = 0 + + # vector from detector pixel 0 to 1 + vectors[i, 4] = np.cos(angles[i]) * proj_geom['DetectorWidth'] + vectors[i, 5] = np.sin(angles[i]) * proj_geom['DetectorWidth'] + proj_geom_out = ac.create_proj_geom( + 'parallel_vec', proj_geom['DetectorCount'], vectors) + + elif proj_geom['type'] == 'fanflat': angles = proj_geom['ProjectionAngles'] vectors = np.zeros((len(angles), 6)) for i in range(len(angles)): @@ -251,3 +271,37 @@ def geom_2vec(proj_geom): raise ValueError( 'No suitable vector geometry found for type: ' + proj_geom['type']) return proj_geom_out + + +def geom_postalignment(proj_geom, factor): + """Returns the size of a volume or sinogram, based on the projection or volume geometry. + + :param proj_geom: input projection geometry (vector-based only, use astra.geom_2vec to convert conventional projection geometries) + :type proj_geom: :class:`dict` + :param factor: Optional axis index to return + :type factor: :class:`float` + """ + + if proj_geom['type'] == 'parallel_vec' or proj_geom['type'] == 'fanflat_vec': + for i in range(proj_geom['Vectors'].shape[0]): + proj_geom['Vectors'][i,2] = proj_geom['Vectors'][i,2] + factor * proj_geom['Vectors'][i,4]; + proj_geom['Vectors'][i,3] = proj_geom['Vectors'][i,3] + factor * proj_geom['Vectors'][i,5]; + + elif proj_geom['type'] == 'parallel3d_vec' or proj_geom['type'] == 'cone_vec': + + if len(factor) == 1: + for i in range(proj_geom['Vectors'].shape[0]): + proj_geom['Vectors'][i,3] = proj_geom['Vectors'][i,3] + factor * proj_geom['Vectors'][i,6]; + proj_geom['Vectors'][i,4] = proj_geom['Vectors'][i,4] + factor * proj_geom['Vectors'][i,7]; + proj_geom['Vectors'][i,5] = proj_geom['Vectors'][i,5] + factor * proj_geom['Vectors'][i,8]; + + elif len(factor) > 1: + for i in range(proj_geom['Vectors'].shape[0]): + proj_geom['Vectors'][i,3] = proj_geom['Vectors'][i,3] + factor[0] * proj_geom['Vectors'][i,6] + factor[1] * proj_geom['Vectors'][i, 9]; + proj_geom['Vectors'][i,4] = proj_geom['Vectors'][i,4] + factor[0] * proj_geom['Vectors'][i,7] + factor[1] * proj_geom['Vectors'][i,10]; + proj_geom['Vectors'][i,5] = proj_geom['Vectors'][i,5] + factor[0] * proj_geom['Vectors'][i,8] + factor[1] * proj_geom['Vectors'][i,11]; + else: + raise ValueError('No suitable geometry for postalignment: ' + proj_geom['type']) + + return proj_geom + |