[Insight-users] DeformationFieldTransform vs LandmarkBasedTransformInitializer

[Dawood Al Masslawi]

Hi David,

There are 3 code samples of the ICP method in the "/Registration"

directory of the ITK examples.

The following article in the Insight Journal also has a simple example

on how do do landmark registration using the kernel transforms,

http://hdl.handle.net/1926/494

<http://hdl.handle.net/1926/494>Best regards,

Dawood




On Tue, Jul 5, 2011 at 4:42 PM, David Doria <daviddoria at gmail.com> wrote:

> Hi Dawood,
>
> I don't see a class named anything like IterativeClosestPoint. Do you
> have an example of how to register two images given corresponding
> landmarks?
>
> Thanks,
>
> David
>
>
>
> On Sun, Jul 3, 2011 at 4:19 AM, Dawood Al Masslawi <masslawi at gmail.com>
> wrote:
> > David,
> > You can do a landmark-based registration using the IterativeClosestPoint
> > method
> > included in the ITK, you can also use the kernel transforms in a
> > registration framework
> > to do a non-rigid registration.
> > If you are to use the kernel transforms note that the Jacobian is not
> > implemented in the
> > current classes so you can only use them with the 1+1 and Amoeba
> optimizers
> > (or any other
> > optimizer that doesn't need derivation), however you can use an
> alternative,
> > that is a contribution
> > made by Rupert Brooks to the Insight Journal
> > (http://hdl.handle.net/1926/494) which introduced some
> > improvements to the kernel transform class and its subclasses, namely
> > implementing the Jacobian.
> > It's computation is slow so you should probably use it with high speed
> > metrics (e.g. mean square)
> > and optimizers. It's similarly implemented in the Elastix
> > (elastix.isi.uu.nl).
> > Also recently I came across another ITK-based implementation in the
> > Plastimatch project
> > (plastimatch.org), their lanmark-based registration supports 3 types of
> > Radial Basis Functions,
> > Thin-Plate Spline (global registration), Gaussian (infinite support) and
> > Wendland (compact support, local
> > registration).
> > As for the DeformationFieldTransform, I agree. It only seems logical that
> it
> > would support the more general
> > transforms comparing to the LandmarkBasedTransformInitializer. In
> addition
> > the DeformationFieldTransform
> > has a GetInverse method which might come in handy sometime :)
> > Best regards,
> > Dawood
> >
> >
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
> >
> >
> > Are these the only two classes to do landmark based registration in ITK?
> >
> > I noticed that LandmarkBasedTransformInitializer can only compute a
> > rigid transform while DeformationFieldTransform seem to use a more
> > general transform - is this the intended difference?
> >
> > Thanks,
> >
> > David
>
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