Hi George,

There was a buglet in vecreg on FSL4.0
You either have to include a brain mask in the options, in which case the output will not be zero, or you can download the patched versions (even FSL4.0.1 would do), where the problem is fixed.

For the interpolation, the option writes --interp=trilinear  (note the "=" between --interp and trilinear).

Cheers,
Saad.

On 15 Nov 2007, at 21:38, George P wrote:

Hi all,

I'm trying to use 'vecreg' (part of FSL Diffusion Toolbox, FSL ver 4.0.0
installed on a CentoOS 4 Linux system).

It's supposed to register vector data to another space.  It can apply a
linear transformation calculated with FLIRT to a non-scalar input volume,
for example a diffusion vector field.  The problem is that the output
volume is always zero.

For example:

vecreg -i dti_V1 -o dti_V1_vecreg -r dti_V1 -t reg.mat

dti_V1_vecreg is zero.

Also, I am not able to override the interpolation method (i.e. if I was to
try the '--interp trilinear' flag, I get an error)

I'd really appreciate your feedback.

George P.

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Saad Jbabdi, 
Postdoctoral Research Assistant,  
Oxford University FMRIB Centre

FMRIB, JR Hospital, Headington, Oxford  OX3 9DU, UK
+44 (0) 1865 222545  (fax 222717)
[log in to unmask]    http://www.fmrib.ox.ac.uk/~saad
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