Yes, this is a result of our confusion as to how to handle the changes in area in the average subject. You can actually specify the number of iterations directly in mri_surf2surf with the --nsmooth-in command.
doug DRC SPM wrote: > Dear FreeSurfers, > > My apologies if this is mentioned in the release notes, but I couldn't > find it with a quick search. > > I'm using the following command to smooth some data: > > mri_surf2surf --hemi rh --s average --sval in.mgh --fwhm 20 --tval out.mgh > > Under FreeSurfer version 4.0.3, part of the output is: > Reading in average area average/surf/rh.white.avg.area.mgh > Approximating gaussian smoothing of target with fwhm = 20.000000, > std = 8.493218, with 379 iterations of nearest-neighbor smoothing > > Whereas under FreeSurfer version 4.1.0, I see: > Reading in average area average/surf/rh.white.avg.area.mgh > INFO: fwhm2niters: Fixing group surface area > Approximating gaussian smoothing of target with fwhm = 20.000000, > std = 8.493218, with 290 iterations of nearest-neighbor smoothing > > It seems that there is less actual smoothing occurring for the same > requested FWHM (unless the altered surface area estimate cancels out > somewhere else?), is that correct? > > Since the 20mm itself was fairly arbitrarily chosen in my lab, I'm > wondering whether it would make sense to increase this to get the same > number of iterations (on the same data) with the newer version, so > that results are smoothed by the same amount. Is there a way of > adjusting the FWHM to undo the effect of the above fwhm2niters fix? > > Thanks, > Ged > > P.S. I realise that 4.1.0 is not exactly "new" itself... I'd also be > interested to know whether this has changed again in more recent > versions. Thanks! > _______________________________________________ > Freesurfer mailing list > Freesurfer@nmr.mgh.harvard.edu > https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer > > > -- Douglas N. Greve, Ph.D. MGH-NMR Center gr...@nmr.mgh.harvard.edu Phone Number: 617-724-2358 Fax: 617-726-7422 In order to help us help you, please follow the steps in: surfer.nmr.mgh.harvard.edu/fswiki/BugReporting _______________________________________________ Freesurfer mailing list Freesurfer@nmr.mgh.harvard.edu https://mail.nmr.mgh.harvard.edu/mailman/listinfo/freesurfer
