Hi Anda. You have a reasonable FOV so I would expect that you can safely
use the maximum DOF (12) and it does sound like this is giving you the
best results so I would go with that. You would want to use reduced DOF if
either a) you are using a strfuctural as intermediate in a 2-step
registration (and therefore don't need 12DOF for the funct->struc
registration assuming your voxel size is set right) or b) you have smaller
FOV (say <100mm).
Cheers.
On Wed, 29 Oct 2003, Anda Pacurar wrote:
> Hi ,
>
> I have a question regarding the choice of DOF in registration.
>
> How can I decide about the number of DOF ?
>
> My functional images have a FOV of 200 mm.
>
> I've made a test. I have registered data to MNI template using 7DOF and
> then 12DOF. When I was using 12DOF images were more close to template.
> I wonder how much is lost from individual data by using 12DOF.
>
> Thank you.
> Anda
>
Stephen M. Smith DPhil
Associate Director, FMRIB and Analysis Research Coordinator
Oxford University Centre for Functional MRI of the Brain
John Radcliffe Hospital, Headington, Oxford OX3 9DU, UK
+44 (0) 1865 222726 (fax 222717)
[log in to unmask] http://www.fmrib.ox.ac.uk/~steve
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