Is there any reason to avoid using the "affine only" setting in the
spatial normalization module? I would have thought that would give an
affine transform that's more general (flexible) than rigid body.
Two more questions on within-subject registration in longitudinal VBM:
* Is there any reason to prefer rigid body over affine?
* Is there a reason why, when doing rigid body, "coregistration" (which
I assume is still more general (inter-modal)) is recommended and
"realign" is never mentioned?
Best,
S
-----Original Message-----
From: John Ashburner [mailto:[log in to unmask]]
Sent: Monday, November 03, 2008 7:17 AM
To: Fromm, Stephen (NIH/NIMH) [C]; [log in to unmask]
Subject: Re: [SPM] Longitudinal VBM: non-rigid-body affine coreg?
There is nothing possible via the user-interface, but if you can do a
bit of
basic MATLAB coding, then a slight tweek to the estimate function of
spm_config_coreg.m (around line 280) from:
x = spm_coreg(strvcat(job.ref), strvcat(job.source),job.eoptions);
to:
job.eoptions.params = [0 0 0 0 0 0 1 1 1 0 0 0]
x = spm_coreg(strvcat(job.ref), strvcat(job.source),job.eoptions);
should do the trick. I can't promise that it will work well though.
Best regards,
-John
On Friday 31 October 2008 15:04, Stephen J. Fromm wrote:
> I'm working out an analysis path for longitudinal VBM in rhesus
monkeys
> using SPM5.
>
> Because the earliest timepoint is at a juvenile stage, and the last is
at
> adult, I'm worried that SPM's coregistration routine (via the
"Coregister"
> button) won't be flexible enough, as it uses rigid body transforms
only.
>
> Is there a way to do coreg in SPM using a more general affine
> transformation?
>
> TIA,
>
> S
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