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?
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.
> -----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.