[Insight-users] Landmark Fitting

[Luis Ibanez]

Hi Xenios,

ITK offers a good set of point-based transformations.

Please take a look at the following classes:

http://www.itk.org/Insight/Doxygen/html/classitk_1_1ThinPlateSplineKernelTransform.html
http://www.itk.org/Insight/Doxygen/html/classitk_1_1ThinPlateR2LogRSplineKernelTransform.html
http://www.itk.org/Insight/Doxygen/html/classitk_1_1ElasticBodyReciprocalSplineKernelTransform.html
http://www.itk.org/Insight/Doxygen/html/classitk_1_1ElasticBodySplineKernelTransform.html
http://www.itk.org/Insight/Doxygen/html/classitk_1_1VolumeSplineKernelTransform.html

All of them require the user to provide two set of landmarks (points).

On set of landmarks is associated with the source space
and the other set is associated with the target space.

 From both sets, a SplineKernel interpolation is perfomed.

The classes above differ in the type of kernel used for the
interpolation.

This classes are based on the paper:

"A Physics-Based Coordinate Transformation for 3-D Image Matching"
by Davis, Khotanzad, Flaming and Harms,
IEEE-TMI, Vol. 16 No.3 June 1997

You may also want to take a look at the following
example which visualize the effect of the interpolation:

    http://www.itk.org/HTML/ThinPlateSplines.htm

The code can be found at:

Insight/Examples/ThinPlateSpline

If you have additional methods for landmark-based transform
and you are willing to contribute them to ITK we will be glad
to help you do so.


Please let us know if you would like to know any additional
details.


Thanks

Luis


========================================================

Xenios Papademetris wrote:
> Hi,
> 
> We are in the process of implementing a point-based registration scheme 
> (both rigid/non-rigid) in ITK. Is there any class that allows one to fit 
> a transformation using a set of corresponding landmarks (as 
> vtkLandmarkTransform in VTK).
> 
> If not and assuming that one is interested in doing this for both rigid 
> and non-rigid transformations (we have code to do this outside of ITK) 
> does anybody have any suggestions as to where in the ITK hierarchy such 
> a class would fit.
> 
> (In our current implementation we use (i) For our BSpline Transformation 
> mode we initialize using an ad-hoc method and then to do steepest 
> descent optimization until the distance between the landmarks is 
> minimized. We use vtkLandmarkTransform for the linear stuff)
> 
> Thanks
> 
> Xenios
> _____________________________________________________________________
> Xenios Papademetris             papad@noodle.med.yale.edu
> Associate Research Scientist         http://noodle.med.yale.edu/~papad
> Image Processing and Analysis Group, Yale University
> ______________________________________________________________________
> 
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