[Insight-users] DeformationFieldTransform vs LandmarkBasedTransformInitializer

[Dawood Al Masslawi]

David, Brian,

We had a discussion a while back about the difference between a

transform and a warping,

http://www.itk.org/pipermail/insight-users/2011-May/041192.html

<http://www.itk.org/pipermail/insight-users/2011-May/041192.html>my
understanding is that theoretically transforms map elements

from the source space to a target space but a warping maps elements

from the target space to the source space (in most cases).

This will result in some practical differences between the two, transforms

will be more complicated since the properties of the input and output

space are quite likely to have major differences, it seems that the purpose

of the WarpImageFilter was to make things simpler (?!!), however

using the DeformationFieldTransform might result in more flexibility.

It all depends on how the DeformationFieldTransform is implemented.

ITK-wise as you can see in,

http://www.itk.org/Doxygen/html/classitk_1_1DeformationFieldTransform.html

and

http://www.itk.org/Doxygen/html/classitk_1_1WarpImageFilter.html

the DeformationFieldTransform supports most common properties

of other transform filters (although one wonders, could it be used in a

registration scenario just like other transforms?!!) and all the

WarpImageFilter does is using the deformation field to back-map the

pixles.

Did you see any differences in the output image of either filters?

Dawood




On Tue, Jul 5, 2011 at 9:59 PM, David Doria <daviddoria at gmail.com> wrote:

> On Tue, Jul 5, 2011 at 8:42 AM, Dawood Al Masslawi <masslawi at gmail.com>
> wrote:
> > 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
> > Best regards,
> > Dawood
>
> Could you explain the difference between WarpImageFilter and
> DeformationFieldTransform ?
>
> These seem to do the same thing:
> http://www.itk.org/Wiki/ITK/Examples/Registration/WarpImageFilter
> http://www.itk.org/Wiki/ITK/Examples/Registration/DeformationFieldTransform
>
> David
>
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