This is a bit of a hack, but it should work.

First, create an LTA file using tkregister, eg,

tkregister --targ vol0.5mm.mgz --mov vol1mm.mgz --regheader --reg deleteme.dat --ltaout reg.lta --noedit

Now create a registration file based on the "vox2ras" matrices in the two volumes. You can get these with

mri_info --vox2ras vol0.5mm.mgz mri_info --vox2ras vol1mm.mgz

Call these Va and Vb respectively

Now compute R = Va*inv(Vb)

Edit the reg.lta file to put the values for R in the file. There is a lot of stuff in that file, including a 4x4 matrix just above "src volume info". Replace this matrix with R

Now use mri_surf2surf to transform the surface into the 0.5mm space, something like

mri_surf2surf --reg reg.lta --s subject --sval-xyz white --tval-xyz vol0.5mm.mgz --tval ./lh.white.0.5mm

It may take some playing around to get it right (eg, try reversing the targ and mov (and Va Vb))

On 12/19/2017 07:33 AM, Luqi Cheng wrote:

Deer Freesurfer Experts,

I'm dealing with the monkey data. I convert the 0.5mm resolution monkey data into "fake" 1mm space using "mri_convert -iis 1 -ijs 1 -iks 1 "and create surfaces. I want to obtain the white/grey matter inferface in the raw 0.5mm volume space from white surface. I use the mri_surf2vol command but it is larger than the raw 0.5mm space.  How could I acquire the white/grey matter inferface in the raw 0.5mm space ?

Thank you very much.

Best, Luqi

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