Hi
short note aside: if at all possible, you should register from low to
highres and then invert (using convert_xfm) the transformation (rather
than registering highres to lowres directly). Always use the 'better'
image as reference, that will improve accuracy.
best
christian
On 25 Nov 2003, at 01:17, Hoang Tran wrote:
> Hi Mark,
>
> We ran into the FLIRT 5.0 segmentation violation issue on RedHat 9. The
> images that cause the problems are located at:
>
> http://www.nbresearch.com/data/FlirtSegViolationImages.zip
>
> This file contains two sets of images: T1 (high resolution) and ref-T1
> (low
> resolution)
>
>
> The command that we used which triggers the segmentation error is:
>
> flirt -in T1 -ref ref-T1 -out foo
>
> The interesting thing is that the problem doesn't occur for every T1
> image
> we have and it only occurs when trying to register the higher
> resolution T1
> image to the lower resolution reference image.
>
> In any case, running with verbose set at a high level shows that the
> problem always occurs just after:
>
>>> copy U UE
>>> if MAXDOF > 9
>>> clear U
>>> if MAXDOF > 9
>>> optimise 12 UE:1 0.0 0.0 0.0 0.0 0.0 0.0 0.0 rel 2
> Coarse rotation samplings are:
> -1.570796 -0.523599 0.523599 1.570796
> -1.570796 -0.523599 0.523599 1.570796
> -1.570796 -0.523599 0.523599 1.570796 ...
>
> If any further information to debug the problem is needed, then please
> let
> me know.
>
> -Hoang
>
--
Christian F. Beckmann
Oxford University Centre for Functional
Magnetic Resonance Imaging of the Brain,
John Radcliffe Hospital, Headington, Oxford OX3 9DU, UK
Email: [log in to unmask] - http://www.fmrib.ox.ac.uk/~beckmann/
Phone: +44(0)1865 222782 Fax: +44(0)1865 222717
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