Hi Bruce,
They have the same geometry, but didn't have the same center (128 128 128 vs 128 118 72). I guess freeview doesn't not show this difference, or handle it in a different way than mris_calc. Nevertheless, when both volumes have the same center (mri_convert -oc 0 0 0), the mris_calc -o out.mgz binF2.mgz mul binF1.mgz gives the correct and expected result. Should have checked this earlier, but I have been lured by the overlay in freeview.
@ Rudolph : "problem" solved. I didn't express myself correctly, sorry about that. The content of binF1 and binF2 were absolutely not modified, the input volume was "shifted" (see why below) so that the resulting volume was different from what we expected when seeing the overlay in freeview.
Best,
Christopher
On 12.10.2012 16:57, Bruce Fischl wrote:
Hi Christophe
what does mri_info tell you about them? Are they the same geometry? Bruce On Fri, 12 Oct 2012, Christopher Coello wrote:
Dear Freesurfer community,
Using freeview, I can visualize that two binary volumes are overlaying in some parts. freeview -v binF1.mgz -v binF2.mgz
When using the command mris_calc -o out.mgz binF1.mgz mul binF2.mgz to create the intersection of these two volumes, I obtain a file with only zeros. To debug, I added the two volumes mris_calc -o out.mgz binF1.mgz add binF2.mgz I was surprise to see that one of the volumes (binF1) is shifted of tens of voxels along an axis. When doing mris_calc -o out.mgz binF2.mgz add binF1.mgz, the binF2 is shifted.
Is that a bug ?
mris_calc : v.1.37.2.4 2011/04/04 freeview : v1.0 2011/05/22
Best,
Christopher
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