Additional functions: the functions module

Additional functions for PyAstraToolbox.

astra.functions.add_noise_to_sino(sinogram_in, I0, seed=None)

Adds Poisson noise to a sinogram.

Parameters:

• sinogram_in (numpy.ndarray) – Sinogram to add noise to.
• I0 (float) – Background intensity. Lower values lead to higher noise.

Returns:

numpy.ndarray – the sinogram with added noise.

astra.functions.clear()

Clears all used memory of the ASTRA Toolbox.

Note

This is irreversible.

astra.functions.data_op(op, data, scalar, gpu_core, mask=None)

Perform data operation on data.

Parameters:

• op – Operation to perform.
• data – Data to perform operation on.
• scalar – Scalar argument to data operation.
• gpu_core – GPU core to perform operation on.
• mask – Optional mask.

astra.functions.geom_2vec(proj_geom)

Returns a vector-based projection geometry from a basic projection geometry.

Parameters:proj_geom (dict) – Projection geometry to convert

astra.functions.geom_size(geom, dim=None)

Returns the size of a volume or sinogram, based on the projection or volume geometry.

Parameters:

• geom – Geometry to calculate size from
• dim (int) – Optional axis index to return

astra.functions.move_vol_geom(geom, pos, is_relative=False)

Moves center of volume geometry to new position.

Parameters:

• geom (dict) – Input volume geometry
• pos (tuple) – Tuple (x,y[,z]) for new position, with the center of the image at (0,0[,0])
• is_relative (bool) – Whether new position is relative to the old position

Returns:

dict – Volume geometry with the new center