[MINC-users] voxel coordinates in native space vs.
Alex ZIJDENBOS
alex@bic.mni.mcgill.ca
Fri May 21 09:50:05 2004
Of course, there are also the utilities
worldtovoxel
and
voxeltoworld
which do exactly what you want.
-- Alex
On Fri, May 21, 2004 at 07:34:27PM +1000, Andrew Janke wrote:
> On Tue, 18 May 2004, Jeni Chen wrote:
>
> > I'm just wondering if anyone knew how to convert a set of tal coordinates
> > back into native space (i.e finding the equivalent). For instance, take
> > the Talairach coordinates 6 -8 44. In register we see the corresponding
> > voxel coordinates as 48 59 58. But if I want to look for the exact same
> > peak in the original raw data, how can I find it? Is there a
> > program or mathematical formula to do it?
>
> Jeni,
>
> All you need do is find the .xfm file that was generated to register your file
> to talairach space (assuming you used mritotal to do this).
>
> Have a look at this file, it contains a truncated 4x4 affine transformation
> matrix (assuming you did a linear fit only), the last row (0 0 0 1) is not
> stored.
>
> Then just take your point in talairach space, transform this by the inverse of
> the Matrix in the .xfm file and you have your point in native space. MATLAB or
> octave may prove handy to do this matrix calculation.
>
>
> --
> Andrew Janke ( rotorATcmr.uq.edu.au || www.cmr.uq.edu.au/~rotor )
> Australia->University of Queensland->Centre for Magnetic Resonance
> W: +61 7 3232 7254 || H: +61 7 3800 4042 || M: +61 4 2138 8581
> _______________________________________________
> MINC-users@bic.mni.mcgill.ca
> http://www.bic.mni.mcgill.ca/mailman/listinfo/minc-users
--
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| Alex P. Zijdenbos, Ph.D. | |
| McConnell Brain Imaging Centre | Phone: [+1] 514 398-5220 (office) |
| Montreal Neurological Institute | [+1] 514 398-1996 (dept.) |
| 3801 University St., WB-208 | Fax: [+1] 514 398-8952 (office) |
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