The smoothing works through iterative nearest neighbor smoothing, so the fwhm is essentially discretized because you can't have fractions of an iteration. It looks like fwhm=0.66 is closer to 0 iterations than 1 iteration, so it chooses 0.
On 12/21/18 11:23 AM, sha...@nmr.mgh.harvard.edu wrote: > Dear Surfers, > I am trying to use mris_fwhm to apply fwhm=0.66 to my fmri data (voxel > size 1 mm iso)using the below command: > > mris_fwhm --s <SBJ_NAME>--hemi rh --smooth-only --i > fmcpr.sm0.self.projfrac_0.rh.nii.gz --fwhm 0.66 --o > fmcpr.sm0p66_surf.self.projfrac_0.rh.nii.gz --mask > /masks/brain.self.rh.nii.gz > > When I apply this command, it works without any error. The message on > screen is as below: > > <SBJ_NAME> rh white > Number of vertices 160391 > Number of faces 320778 > Total area 102725.085938 > GroupSurface 0 > AvgVtxArea 0.640467 > AvgVtxDist 0.875515 > StdVtxDist 0.253406 > Loading mask masks/brain.self.rh.nii.gz > Found 36045 voxels in mask > Not Polynomial detrending > Smoothing input by fwhm=0.660000, gstd=0.280276, niters=0 > Only smoothing, so saving and exiting now > > But the outcome is the same as input. I think it is expected based on > (niters=0). When I use the same command with fwhm =1, then i see the > difference and niters=1. > > My question is, why is fwhm = 0.66 not acceptable? How can i solve this > issue. > > Regards > > _____________________________________ > > Shahin Nasr > > Assistant Prof. in Radiology > Harvard Medical School > Martinos Imaging Center, MGH > Bldg 149, 13th street, > Charlestown, MA 02129 > > _______________________________________________ > Freesurfer mailing list > Freesurfer@nmr.mgh.harvard.edu > https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer _______________________________________________ Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer
