Hello @ibr,
Got it, that notebook has nothing to do with what you want.
In SimpleITK we only exposed the option of BSpline interpolation as a constant to the ResampleImageFilter. This is based on the work of Unser and others as documented in the original ITK BSplineInterpolateImageFunction class. We do not expose the functionality that you want as it is not “Simple” and SimpleITK is a simplified interface.
For what you are looking you should go to ITK (not sure that it provides the image derivative using the B-spline representation, but the ITK code should be a good start).