[Insight-developers] Multi-resolution pyramid and multi-resolution PDE deformable registration small issues

[Tom Vercauteren]

Hi all,

I just saw a few weird things in some multi-resolution objects.

First of all, the MultiResolutionPyramidImageFilter will always
produce a blurred image even with an all one schedule. This is because
the input it always smoothed to produce the output. If the schedule at
a given level is all one, the sigma of the Gaussian will be 0.5.

This case is better handled in
RecursiveMultiResolutionPyramidImageFilter. In that class, if the
schedule is all one, the output will only be a casted version of the
input. This makes more sense to me.

Would anyone mind if I changed the behavior of
MultiResolutionPyramidImageFilter to perform the same operation as
RecursiveMultiResolutionPyramidImageFilter in the case of all one
schedule?


Also it seems that RecursiveMultiResolutionPyramidImageFilter should
be the default image pyramid class for most applications. It is more
efficient than MultiResolutionPyramidImageFilter when the schedule is
downward divisible and falls back to MultiResolutionPyramidImageFilter
when it is not.

Would anyone mind if I changed the default image pyramid filter in
MultiResolutionPDEDeformableRegistration to be
RecursiveMultiResolutionPyramidImageFilter instead of
MultiResolutionPyramidImageFilter?

Regards,
Tom