Hi Matt - have you tried running avscale which provides a
decomposition of the FLIRT matrix?
Cheers.
On 14 Apr 2009, at 22:50, Matt Glasser wrote:
> Hi,
>
> I am curious as to the exact format of the FLIRT transformation
> matrix. I know that the fourth row is always 0 0 0 1, and that the
> last column holds translations of x, y, z. I am unclear on how the
> other 9 values relate to the rotations, scales, and skews. I am
> dealing with a proprietary processing stream that produces a
> transformation matrix in a different format, and am trying to figure
> out how to convert between the two. For example, a decomposition of
> the non-FLIRT matrix:
>
> 0.059006 -0.934484 0.104069 -10.6780
> -0.001233 0.154435 0.913258 10.4736
> -1.038315 -0.023871 -0.005947 1.3356
> 0.000000 0.000000 0.000000 1.0000
>
> Is
>
> displacement (mm): -10.6779 10.4734 1.3351
> rotation (deg): -88.6358 -87.6168 -6.5889
> stretch (factor): 0.959151 0.904171 1.042409
> stretch ang (deg): 0.5418 -11.3901 38.9531
>
> I am curious what the comparable FLIRT matrix would be.
>
> Thanks,
>
> Matt.
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Stephen M. Smith, Professor of Biomedical Engineering
Associate Director, Oxford University FMRIB Centre
FMRIB, JR Hospital, Headington, Oxford OX3 9DU, UK
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