parker_weighting

odl.applications.tomo.analytic.filtered_back_projection.parker_weighting(ray_trafo, q=0.25)

Create parker weighting for a RayTransform.

Parker weighting is a weighting function that ensures that oversampled fan/cone beam data are weighted such that each line has unit weight. It is useful in analytic reconstruction methods such as FBP to give a more accurate result and can improve convergence rates for iterative methods.

See the article Parker weights revisited for more information.

Parameters

ray_trafoRayTransform

The ray transform for which to compute the weights.

qfloat, optional

Parameter controlling the speed of the roll-off at the edges of the weighting. 1.0 gives the classical Parker weighting, while smaller values in general lead to lower noise but stronger discretization artifacts.

Returns

parker_weighting : ray_trafo.range element

See Also

fbp_op : Filtered back-projection operator from RayTransform tam_danielson_window : Indicator function for helical data odl.applications.tomo.geometry.conebeam.FanBeamGeometry : Use case in 2d odl.applications.tomo.geometry.conebeam.ConeBeamGeometry : Use case in 3d (for pitch 0)

References