[Insight-users] Transformation of vtkPolyData with an itk::Transform

[Lodron, Gerald]

Hi,

Unfortunatelly i am using the bspline transform. I know that the exact inverse is not given but is there a possibility to approximate the inverse of that transform?

Best regards

-----Ursprüngliche Nachricht-----
Von: Sajendra [mailto:sajendra at gmail.com] 
Gesendet: Donnerstag, 17. Dezember 2009 17:57
An: Lodron, Gerald
Cc: insight-users at itk.org; vtkusers at vtk.org
Betreff: Re: [Insight-users] Transformation of vtkPolyData with an itk::Transform

Hello Gerald,

You will likely need to use the inverse of the transform computed from itk registration to transform your vtk polydata.
The transform you have maps points from the fixed image space into the moving image space (so that it can be used to resample the moving image). If you want to transform points from the moving image space into the fixed image space, you need the inverse of that transform.

Regards,
Sajendra



On Thu, Dec 17, 2009 at 5:27 AM, Lodron, Gerald <Gerald.Lodron at joanneum.at> wrote:
> Hello
>
> I currently made a point selector which stores it's points into a vtkPolyData structure.
>
> Now I successfully made a image registration which converted the vtk image into itk, registered (transformed with itk::ResampleImageFilter) it and converted it back to vtk for visualization. Now the points of the vtkPolyData object are misaligned and I need to transform them. My point transformation implementation looks like this:
>
>
>
> The problem is that the points does not fit to their old position, so there must be something wrong with the transformPoint operation?
>