Helper class: the ASTRAProjector module

class astra.ASTRAProjector.ASTRAProjector2D(proj_geom, vol_geom, proj_type, useCUDA=False)

Bases: object

Helps with various common ASTRA Toolbox 2D operations.

This class can perform several often used toolbox operations, such as:

• Forward projecting
• Back projecting
• Reconstructing

Note that this class has a some computational overhead, because it copies a lot of data. If you use many repeated operations, directly using the PyAstraToolbox methods directly is faster.

You can use this class as an abstracted weight matrix \(W\): multiplying an instance proj of this class by an image results in a forward projection of the image, and multiplying proj.T by a sinogram results in a backprojection of the sinogram:

proj = ASTRAProjector2D(...)
fp = proj*image
bp = proj.T*sinogram

Parameters:

• proj_geom (dict) – The projection geometry.
• vol_geom (dict) – The volume geometry.
• proj_type (string) – Projector type, such as 'line', 'linear', ...
• useCUDA (bool) – If True, use CUDA for calculations, when possible.

backProject(data)

Backproject a sinogram.

Parameters:data (numpy.ndarray or int) – The sinogram data or ID. Returns:numpy.ndarray – The backprojection.

forwardProject(data)

Forward project an image.

Parameters:data (numpy.ndarray or int) – The image data or ID. Returns:numpy.ndarray – The forward projection.

reconstruct(data, method, **kwargs)

Reconstruct an image from a sinogram.

Parameters:

• data (numpy.ndarray or int) – The sinogram data or ID.
• method (string) – Name of the reconstruction algorithm.
• kwargs – Additional named parameters to pass to astra.creators.create_reconstruction().

Returns:

numpy.ndarray – The reconstruction.

Example of a SIRT reconstruction using CUDA:

proj = ASTRAProjector2D(...)
rec = proj.reconstruct(sinogram,'SIRT_CUDA',iterations=1000)

class astra.ASTRAProjector.ASTRAProjector2DTranspose(parentProj)

Implements the proj.T functionality.

Do not use directly, since it can be accessed as member .T of an ASTRAProjector2D object.