Base Parameters

The following documents the base parameters used by the TomographyModel class. Any of these parameters can be modified with TomographyModel.set_params().

Parameters that are specific to particular geometries are documented in the geometry’s documentation.

Reconstruction Parameters

sharpnessfloat (Defaults to 1.0)

Specifies the sharpness of the reconstruction. Larger values produce sharper images. Smaller values produce softer images.

snr_dbfloat (Defaults to 30.0)

Specifies the assumed signal-to-noise ratio in dB of the sinogram data. Larger values produce sharper and more edgy images. Smaller values produce softer and less edgy images.

verboseint (Defaults to 1)

Larger values produce more status information. Change to 0 for silent operation or 2 or 3 for more detailed output.

use_gpustring (Defaults to ‘automatic’)

Possible values are ‘automatic’, ‘full’, ‘sinograms’, ‘worker’, ‘none’. ‘full’ tries to perform the entire reconstruction on the gpu; ‘sinograms’ uses the GPU for all of the sinogram storage and calculations but uses CPU memory for the reconstructions; ‘worker’ uses the CPU for some computations and the GPU for projections only (to conserve memory); ‘automatic’ tries to determine the appropriate choice based on available memory; ‘none’ disables GPU use.

Geometry Parameters

recon_shapetuple (num_rows, num_cols, num_slices)

Array size of reconstruction. This is set automatically and is available from get_params('recon_shape')(). It is recommended to use scale_recon_shape() to increase this by a factor of 10-15% when the object extends beyond the field of view.

delta_det_channelfloat (Defaults to 1.0)

Spacing between detector channels in ALU.

delta_det_rowfloat (Defaults to 1.0)

Spacing between detector rows in ALU.

det_channel_offsetfloat (Defaults to 0.0)

Assumed offset between center of rotation and center of detector between detector channels in ALU.

det_row_offsetfloat (Defaults to 0.0)

Assumed offset in rows of the source-to-detector line with center of detector in ALU.

delta_voxelfloat (Defaults to 1.0)

Spacing between voxels in ALU.

Proximal Map Parameters

sigma_yfloat (Defaults to 1.0)

Assumed standard deviation of sinogram noise.

sigma_pfloat (Defaults to 1.0)

Proximal map parameter.