OpTomo class: the `optomo` module

class astra.optomo.OpTomo(*args, **kwargs)[source]

Bases: LinearOperator

Object that imitates a projection matrix with a given projector.

This object can do forward projection by using the * operator:

W = astra.OpTomo(proj_id)
fp = W*image
bp = W.T*sinogram

It can also be used in minimization methods of the scipy.sparse.linalg module:

W = astra.OpTomo(proj_id)
output = scipy.sparse.linalg.lsqr(W,sinogram)

BP(s, out=None)[source]

Perform backprojection.

Output must have the right 2D/3D shape. Input may also be flattened.

Output must also be contiguous and float32. This isn’t required for the input, but it is more efficient if it is.

:param : The projection data. :type s: numpy.ndarray :param out: Array to store result in. :type out: numpy.ndarray

FP(v, out=None)[source]

Perform forward projection.

Output must have the right 2D/3D shape. Input may also be flattened.

Output must also be contiguous and float32. This isn’t required for the input, but it is more efficient if it is.

Parameters:

reconstruct(method, s, iterations=1, extraOptions=None)[source]

Reconstruct an object.

Parameters:

method (string) – Method to use for reconstruction.
s (numpy.ndarray) – The projection data.
iterations (int) – Number of iterations to use.
extraOptions (dict) – Extra options to use during reconstruction (i.e. for cfg[‘option’]).

Implements the transpose operator.

class astra.optomo.OpTomoTranspose(*args, **kwargs)[source]

Bases: LinearOperator

This object provides the transpose operation (.T) of the OpTomo object.

Do not use directly, since it can be accessed as member .T of an OpTomo object.

Adjoint matrix-vector multiplication.

Applies A^H to x, where A is an M x N linear operator (or batch of linear operators) and x is a row vector (or batch of such vectors).

Parameters

x{matrix, ndarray}: An array with shape (..., M) representing a row vector (or batch of row vectors), or an array with shape (M, 1) representing a column vector.

Added in version 1.18.0: A FutureWarning is now emitted for column vector input of shape (M, 1), for which an array with shape (N, 1) is returned. rmatmat can be called instead for identical behaviour on such input.

This method wraps the user-specified rmatvec routine or overridden _rmatvec method to ensure that y has the correct shape and type.