[MINC-users] nu_correct & masking

[Alex ZIJDENBOS]

Just to chip in: AFAIK it does hurt N3 if you give it data it should
not optimize over. In other words, assuming you care about the brain
only, I believe it does help to provide a brain mask such that it
doesn't try to uniformize scalp/neck/etc.

-- A

On Wed, Jul 27, 2005 at 12:26:16AM -0400, Andrew Janke wrote:
> Hi Richard,
> 
> I had hoped that John Sled would bite on this one, but it appears not
> so here's my thoughts...
> 
> My feeling is that (2) is better.  The more data you give N3 to smooth
> over the better it is going to perform. As far as I am aware, N3 does
> not optimise over peaks per-se but rather the histogram in general. 
> Thus as you way, the more "information" in the image the better.
> 
> Myself I tend to run nu_correct without a mask altogether beyond any
> masking it does internally.
> 
> Andrew
> 
> 
> On 12/07/05, Richard Boyes <rboyes@dementia.ion.ucl.ac.uk> wrote:
> > Hello everybody
> > 
> > Regarding use of a mask with nu_correct, I have available
> > to me two types:
> > 
> > 1. A brain mask that excludes CSF completely - ie WM, GM
> >     only
> > 
> > 2. A 'filled' brain mask - ie includes the CSF in the sulcal
> >     and ventricular spaces.
> > 
> > My question is, which mask is more effective? Intuitively
> > I thought that the CSF mask would be better, as it gives 3
> > classes in the histogram, which gives N3 3 histogram peaks
> > to optimize over.
> > 
> > Thanks in advance
> > Richard
> > _______________________________________________
> > MINC-users@bic.mni.mcgill.ca
> > http://www.bic.mni.mcgill.ca/mailman/listinfo/minc-users
> > 
> 
> 
> -- 
> Andrew Janke      (a.janke@gmail.com || www.cmr.uq.edu.au/~rotor)
> Canada->Montreal                                   Cell: +1 (514) 924 2012
> 
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