[Insight-users] Free form deformation registration

[Kris Thielemans]

Hi

if with FreeForm you mean something that allows local deformations, then the
answer is yes. It's actually described the Software Guide (on the website).

However, there doesn't seem to be a polished application that does it for
you. you have to build your won. Place to start are the
Examples/Registration files (discussed in the Software Guide). That's what
I'm trying to do myself at the moment.

Some helpful pointers maybe:
- all examples are either 2d or 3d, but easy to fairly modify to the other
dimension.
- I'd advice you to get rid of the cast statements at the end, and make sure
that everything happens in floating point (at least to start off with). I've
been struggling for a few days till I finally understood that my images had
max values less than 1, and casting them to unsigned char at output doesn't
leave a lot of interesting data behind... (I know I know, that's just stupid
of me).


Having said that, the only one that I can get some reasonable results with
on my data (simulated CT images using the NCAT phantom, so a bunch of
uniform regions, one for every organ), is the 2nd example which uses the
demons algorithm. All the rest refuses to do anything to my images. That's
obviously because I don't know/understand the parameter settings. Still a
lot to learn.

Good luck

Kris Thielemans
Hammersmith Imanet, part of GE Healthcare
London W12 ONN, United Kingdom