[Insight-users] Demons deformable Registration: initialization and RoI

[Jan Schreiber]

Hi all, 

I have two questions on demons deformable registration:

1. Initialization from non-deformable pre-registration
Before performing the deformable registration, I am using a similarity transform to pre-align the images. Now I want to use the result from the pre-registration with my deformable registration. 
a) is there a simple way to do this?
b) does it make sense to compute a deformation field fom the similatity transform and use this as initial deformation field, is this supported by itk
c) should I just resample the image with the similarity transform and use the "new" image?

2. Setting a region of interest for the deformable registration
a) Is it possible to set a region of Interest to the deformable registration to not register the whole image?
b) If not and I have to extract a region and create a new image from that - is it (easily) possible to re-integrate that region to the original (large) image?

Thanks in advance, 
Jan