[Insight-users] Inversion of transformation fields

[Luis Ibanez]

Ralf,

There is also an iterative implementation....

http://www.itk.org/Insight/Doxygen/html/classitk_1_1IterativeInverseDeformationFieldImageFilter.html


Regards,


    Luis


----------------------
Floca, Ralf wrote:

> Hello everyone.
> 
> I am working on different registration approaches. Some of them consists
> of more then one registration steps (e.g. rigid preregistration and non
> rigid registration). All of them are data driven, so working directly on
> the image. But in some cases, there are some additional information like
> reference points (e.g. fiducals) attached. To keep them up to date
> through out the whole registration process, they also must be
> transformed.
> Now the problem. ITK uses back transform to ensure dense images. This is
> appropriate for the registration of the image itself, but to transform
> meta information (like reference points, to have them up to date in
> interim registration steps) a transform from moving to result image is
> needed. In cases of a rigid registrations I could use the back transform
> function for every single point to achieve this. But the fem, for
> example, only produces a transformation field and has no back transform
> or inversion capabilities.
> Are there any suitable methods to invert this field to achieve a
> transform of points from the moving image space to the result image
> space?
> The easy way: inverting all vectors of the field would only be a
> solution, if the spacing was infinitesimal (whish it was so). So this
> would be no solution.
> 
> I am thankful for every reply and comments.
> 
> Thanks and best regards,
> Ralf o Floca
> 
> ---------------------------------------------------------------------
> Ralf Floca
> University of Heidelberg                           
> Institute for Medical Biometry and Informatics
> Department of Medical Informatics
> Im Neuenheimer Feld 400            
> D-69120 Heidelberg, Germany             Tel. : 06221/56-7484  
> http://www.med.uni-heidelberg.de/mi     Fax  :         -4997    
> ralf_floca at med.uni-heidelberg.de        Sekr.:         -7483
> ---------------------------------------------------------------------
> 
>  
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