[Insight-users] Wierd artifact when doing image registration

[motes motes]

I am currently comparing the itkBSplineDeformableTransform with my own
modifed version of the BSplineTransform.

I run the registration for 25 iterations. For the itk version I get a
final metric value of 681. For my modified version I get the final
metric value 679 so its a slight improvement. But when I look at the
produced registered image it has some wierd squares:

http://img38.imageshack.us/img38/2715/artifact.jpg

any ideas on what might be causing this?