There are two matrices in the headers of the "imported" images. One of
these (the one that SPM mostly uses - mat) shows the imported images
from different subjects in approximate alignment with each other. The
other one (mat0) encodes the mapping back to the original image. You
can get at these by:
Nimp = nifti('rc1xxx.nii')
Nimp.mat
Nimp.mat0
Norig = nifti('xxx.img');
Mapping from the indices of voxels in the imported image, to voxels in
the original involves the following, where x, y and z are the original
indices (numbered from 1..n):
Norig.mat\Nimp.mat0 * [x; y; z; 1]
Best regards,
-John
On Wed, 2010-03-17 at 17:32 +0000, Fabrizio Pizzagalli wrote:
> I'd like to define my ROIs in the native space and to use NewSegment
> function.
>
> You spoke about Deformation tool to obtain the transformations composition
> but I didn't really understand how can I obtain the trasformation that I can use
> to pass from the Native space to the "r*" space.
>
> many thanks,
> Fabrizio
>
>
--
John Ashburner <[log in to unmask]>
|