I think Ged has a solution to this for IRTK <-> FLIRT?
Cheers.
On 21 Jan 2008, at 09:44, Martin Kavec wrote:
> Hi,
>
> I'm trying to convert FSL's 4x4 transform to the IRTK's affine
> transform. I
> have been experimenting on this for quite a while and can not get
> through it.
>
> The main difference is that IRTK dof transform has the origin of the
> rotation
> in the center of the image, while FSL has it in the 0,0,0. So the
> rotation in
> mat causes a translation, which needs to be accounted for in the dof
> matrix.
>
> I decompose translations, rotations, scalings, and skews from from
> the mat
> file and using these I compose the dof transformation. Rotations,
> scalings,
> and skews are simple to get, but since the origins of the mat
> transform is in
> 0,0,0, the transformation includes rotation-related translations as
> well, and
> this is the major problem I have.
>
> So my questions are:
>
> 1. If I have existing FSL affine transform, which maps input image to
> reference using FLIRT, how can I compose an equivalent affine
> transform with
> the origin of rotation in the center of the image and,
>
> 2. if I finally have the transform, and I use avscale to decompose
> it to
> rotations, scales, skews, and translations, if the translations will
> be
> affected by the rotations?
>
> Thanks a lot for ideas in advance.
>
> Martin
>
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Stephen M. Smith, Professor of Biomedical Engineering
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