[Insight-users] FW: Problem with Demons Variant Deformable Registration

[Tom Vercauteren]

Hi Sajendra,

I am glad to hear that you were able to use my code succesfully.

As Torsten pointed out, it should indeed be possible to "get the best
of both worlds". In the code I posted on the Insight Journal, It
should be possible to use a fast symmetric force that behaves very
similarly to the basic symmetric forces demons implementation but has
a reduced computation time.

The difference you experience might be related to different default
parameters. More specifically, from the command line program I posted
you should at least put the following options '-l0.5 -a2 -t0' if you
want to match the basic symmetric forces demons implementation. Of
course you also need to use the same sigmas for smoothing.

Another possible issue might be related to the version of ITK that you
use. I filed a few bug reports anf forgot when they were fixed:
http://www.itk.org/Bug/view.php?id=3985
http://www.itk.org/Bug/view.php?id=3958
http://www.itk.org/Bug/view.php?id=3973
http://www.itk.org/Bug/view.php?id=3972

Let me know if you find other issues.

Best regards,
Tom


On Wed, Apr 9, 2008 at 8:01 PM, Nithiananthan, Sajendra
<Sajendra.Nithiananthan at rmp.uhn.on.ca> wrote:
> Torsten,
>
>  Thanks for the response and pointing me to Tom's implementation.
>  You mentioned there are known problems with the existing implementation,
>  could you point me to the mailing list posts about them? I am not sure if I
>  found them all during my search.
>  I did try Tom's implementation of the fast symmetric force thanks to your
>  suggestion. It worked well, but didn't "converge" in quite as few
>  implementations as the  symmetric forces or fast symmetric forces code that
>  ships with ITK (3.2). But it isn't painfully slow like the former, or have
>  the problems I mentioned previously in the latter. If it is possible to get
>  the best of both worlds I would want to investigate it, or is the fast
>  symmetric implementation that ships with ITK a lost cause? Has anyone else
>  had any experience using it?
>
>  Thanks,
>  Sajendra
>
>
>  > -----Original Message-----
>  > From: Torsten Rohlfing [mailto:torsten at synapse.sri.com]
>  > Hi Sajendra --
>  >
>  > There are some known problems with the fast symmetric demons
>  > forces code
>  > currently in ITK. These have been discussed on the mailing list, but
>  > were never resolved.
>  >
>  > Here's an idea though: Tom Vercauteren of INRIA has provided a vastly
>  > improved variant of the demons algorithm, including among
>  > other features
>  > also a working fast symmetric forces implementation. I
>  > believe his code
>  > is currently in the Review/ directory of the ITK source tree. In any
>  > case, you can also get his original implementation from the
>  > InsightJournal website:
>  >
>  >
>  > http://insight-journal.org/InsightJournalManager/view_publicat
>  > ion.php?back=search.php%3Ftexte%3Dvercauteren&pubid=154
>  >
>  > My suggestion would be for you to give Tom's code a try.
>  > Maybe that will
>  > solve your problems.
>  >
>  > Best,
>  >   Torsten
>  >
>  > --
>  > Torsten Rohlfing, PhD          SRI International, Neuroscience Program
>  >  Research Scientist             333 Ravenswood Ave, Menlo
>  > Park, CA 94025
>  >   Phone: ++1 (650) 859-3379      Fax: ++1 (650) 859-2743
>  >    torsten at synapse.sri.com        http://www.stanford.edu/~rohlfing/
>  >
>  >      "Though this be madness, yet there is a method in't"
>
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