noindent This document describes two new classes that facilitate the use of
the doxygen{BSplineDeformableTransform} in multiresolution registration
algorithms. The first class, doxygen{GridScheduleComputer}, defines the
B-spline grid, based on a user-specified grid spacing and an input image (the
fixed image in registration). A different grid is determined for each
resolution level of the registration, given a multiresolution schedule similar
to that of the image pyramids. The second class,
doxygen{UpsampleBSplineParametersFilter}, resamples (usually upsamples) the
B-spline coefficients to a new control point grid having a different
spacing/origin/size. This can be used to transfer the result from one
resolution level to that of the next level. Summarising, suitable grid
definitions follow from the first class, and are used as input for the second
class, which performs the actual resampling.

The classes are implemented using the Insight Toolkit url{www.itk.org}. This
paper is accompanied with the source code, including a test program.