[MINC-users] nlpfit minctracc

[Andrew Janke]

> Using the following command on two separate computers (yorick and a linux
> machine)
>
> nlpfit -init_xfm lin.xfm source.mnc target.mnc nlin.xfm
> mincblob -det grid.mnc det.mnc
>
> yields differing det.mnc files.   Inside the brain the
> patterns are similar although the values are not exactly the same (within
> about 15%).
>
> yorick 157% minctracc -version
> Package MNI AutoReg, version 0.98k, compiled by swmgr at yorick
> (mips-sgi-irix6.5) on 2003-11-26 at 16:46:16
>
> oliver% minctracc -version
> Package mni_autoreg 0.99.2, compiled by rotor at romeo (i686-pc-linux-gnu) on
> Mon May  8 23:16:34 EDT 2006
>
> What between the two versions could cause the difference between the grid
> files and consequently the det.mnc files?  The fact that most differences
> are outside the brain and on the edges suggests a masking difference but I
> have not defined a mask in either case.

Erk! that is a very old version of minctracc on yorick! There have
been many changes to the way that minctracc does nonlinear fitting
(specifically around the edges of masks) in this time. The most likely
place this occurred was between versions 0.98s and 0.98t.  This is the
NEWS file from then:

Release 0.98t
-------------

* 30% speed increase due to changes in nonlinear fitting code
* Corrected masking in sub-lattice (Patricia Le Nezet and Irina Kezele)


There were also some changes regarding direction cosines reading
errors around 2004 that may be affecting you.
I would suggest that you rely on the results from the later version! :)





-- 
Andrew Janke   (a.janke at gmail.com || http://a.janke.googlepages.com/)
Canberra->Australia    +61 (402) 700 883