The bias correction is used when generating the tissue class images (c*) and
"imported" images (rc*) . If the aim is to do a VBM, then everything should
be taken care of.
Best regards,
-John
On Monday 12 January 2009 16:33, Dana Perantie wrote:
> If I understand correctly, the bias correction info from seg_sn.mat is
> incorporated into the calculation of the flow fields (u*) ... but when
> applying flow fields with Create Warped, the bias correction is not
> applied. Does this mean that people using DARTEL as described in the
> manual are analyzing images without bias correction? Thank you,
> Dana
>
> -----Original Message-----
> From: John Ashburner [mailto:[log in to unmask]]
> Sent: Friday, January 09, 2009 2:57 PM
> To: Dana Perantie; [log in to unmask]
> Subject: Re: [SPM] forward/backward flow, warp, map
>
> > Sorry this question was not clear -- what I meant was: if I use DARTEL's
> > Create Warped to apply u*, is the bias correction information from
> > seg_sn.mat also applied? Thanks,
>
> No. This would need to be done seperately.
>
> Best regards,
> -John
>
> > -----Original Message-----
> > From: SPM (Statistical Parametric Mapping) [mailto:[log in to unmask]] On
> > Behalf Of John Ashburner Sent: Tuesday, January 06, 2009 12:25 PM
> > To: [log in to unmask]
> > Subject: Re: [SPM] forward/backward flow, warp, map
> >
> > > Thank you John for the very important information about the u* files
> > > applying to the original images and not the imported images. I see now
> > > that Create Warped works with both and the script includes a test for
> > > which way to do it.
> > >
> > > Do u* files include the bias correction information from the initial
> > > Segment?
> >
> > The bias correction parameters are saved in the seg_sn.mat file.
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