scico.linop.xray.symcone¶

Cone beam X-ray transform for cylindrically symmetric objects.

Cone beam X-ray transform and FDK reconstruction for cylindrically symmetric objects; essentialy a cone-beam variant of the Abel transform. The implementation is based on code modified from the axitom package [45].

Classes

`AxiallySymmetricVolume`(input_shape[, ...])	Create a volume by axial rotation of a plane.
`SymConeXRayTransform`(input_shape, obj_dist, ...)	Cone beam X-ray transform for cylindrically symmetric objects.

class scico.linop.xray.symcone.AxiallySymmetricVolume(input_shape, input_dtype=<class 'numpy.float32'>, axis=0, center=None)[source]¶

Bases: LinearOperator

Create a volume by axial rotation of a plane.

Parameters:

input_shape (Tuple[int, ...]) – Input image shape.
input_dtype (DType) – Input image dtype.
axis (int) – Index of axis of symmetry (must be 0 or 1).
center (Optional[int]) – If None, defaults to the center of the image on the specified axis. Otherwise identifies the center coordinate on that axis.

class scico.linop.xray.symcone.SymConeXRayTransform(input_shape, obj_dist, det_dist, axis=0, pixel_size=None, num_slabs=1)[source]¶

Bases: LinearOperator

Cone beam X-ray transform for cylindrically symmetric objects.

Cone beam X-ray transform of a cylindrically symmetric volume, which may be represented by a 2D central slice, which is rotated about the specified axis to generate a 3D volume for projection. The implementation is based on code modified from the AXITOM package [45]..

Parameters:

input_shape (Tuple[int, ...]) – Shape of the input array. If 2D, the input is extended to 3D (onto a new axis 1) by cylindrical symmetry.
obj_dist (float) – Source-object distance in arbitary length units (ALU).
det_dist (float) – Source-detector distance in ALU.
axis (int) – Index of axis of symmetry (must be 0 or 1).
pixel_size (Optional[Tuple[float, float]]) – Tuple of pixel size values in ALU.
num_slabs (int) – Number of slabs into which the volume should be divided (for serial processing, to limit memory usage) in the imaging direction.

fdk(y, num_angles=360)[source]¶

Reconstruct central slice from projection.

Reconstruct the central slice of the cylindrically symmetric volume from a projection. The reconstruction makes use of the Feldkamp David Kress (FDK) algorithm implemented in the axitom package.

Parameters:

y (Union[Array, ndarray, bool, number, bool, int, float, complex]) – The projection to be reconstructed.
num_angles (int) – Number of angles to be averaged in the reconstruction.

Returns:

Reconstruction of the central slice of the volume.