[Insight-users] question about b-spline field to a dense deformation field: BSplineDeformableTransform

[Anja Ende]

Hello all,

I have a question about the workings of the BSplineDeformableTransform
and the question is, perhaps, a bit naive but I am trying to
understand some of the workings before I start using it:

So, in a BSplineDeformableTransform the deformation field is
parameterized using uniform B-splines. Now, assuming we are working in
2D, each control point has 2 coefficients for the x and y direction
and it affects 16 neighborhood voxels.

My question is that say we want to extract a dense deformation field
from this parameterised deformation field. Then each voxel is affected
by a few control points. Do we basically add contributions from each
of the control points to obtain the final deformation at each voxel?

Is that what ITK does when we resample an image using this transformation?

Many thanks,

Anja