Improved radial distortion code.
Improved radial distortion code.

Replaced looping with usage of SimpleITK filters to improve runtime
of the radial distortion section.

InsightSoftwareConsortium/SimpleITK-Notebooks,zivy/SimpleITK-Notebooks,InsightSoftwareConsortium/SimpleITK-Notebooks,InsightSoftwareConsortium/SimpleITK-Notebooks,zivy/SimpleITK-Notebooks,zivy/SimpleITK-Notebooks