Hi Robert,
it's a bit complicated for the dreaded "historical" reasons. The surfaces are built from "conformed" volumes (1mm isotropic, with center ras voxel at the center of the volume). It's documented in gory detail (thanks Doug!) at:
http://surfer.nmr.mgh.harvard.edu/fswiki/CoordinateSystems
all of the relevant transforms can be extracted with mris_info (for surfaces) and mri_info (for volumes). If all you want is to extrat the voxel coord for the white or pial surface in one of the conformed volumes it's only a single transform. If you want to get back to the unconformed ones (e.g. the input to recon-all), then you'll need to compose a few of them.
cheers, Bruce
p.s. the voxel coords of a vertex should be the same in all the conformed volumes (orig.mgz, T1.mgz, brainmask.mgz, wm.mgz, etc...)
On Thu, 23 Nov 2006, Roberto Toro wrote:
Hello,
I have a C code that reads FS surfaces and does some processing on them. I would like to map this back to the original MRI volume. Googling around I found that vertex coordinates may correspond to coordinates in the COR volume.... but COR volumes are now deprecated....so two questions:
- what is the relationship between vertex coordinates and volume
coordinates? 2. is there a special volume where vertex coordinates just map volume coordinates?
thank you very much! roberto
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