[vtkusers] vtkProcrustesAlignmentFilter in Rigid Body mode

[Wes Turner]

On Mon, Jul 6, 2009 at 8:46 AM, David Doria
<daviddoria+vtk at gmail.com<daviddoria%2Bvtk at gmail.com>
> wrote:

>
> On Mon, Jul 6, 2009 at 7:29 AM, Thomas Hack <hack at bonn.edu> wrote:
>
>> Hi!
>>
>> I've got a question concerning vtkProcrustesAlignmentFilter (vtkPAF). I
>> want to use it for two sets of landmarks (same number of landmarks and same
>> sequence). I want to register them into the same coordinatesystem using a
>> rigid body transformation. My question now is, how do i get the correspondig
>> transformation matrix? GetLandmarkTransform() gives me a very strange
>> martix, which does for sure not the right transformation. The result of the
>> vtkPAF looks correct to me, but i need the transformation matrix, because i
>> want to register two volumes on base of the landmarks.
>>
>> Does anyone has an idea?
>> Thanks,
>>
>> Tom
>>
>
> I don't see the difference between vtkPAF and vtkLandmarkTransform from
> reading the class descriptions, so I can't comment on vtkPAF, but I have an
> example of a landmark transform here:
> http://www.vtk.org/Wiki/Landmark_Transform
>
> You can get the matrix with ->GetMatrix() (it is type vtkMatrix4x4). Maybe
> you could keep your existing code and try
> GetLandmarkTransform()->GetMatrix() ? Otherwise it sounds like you can just
> use a landmark transform by itself?
>
> Thanks,
>
> David
>
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>
 vtkProcrustesAlignmentFilter takes an ensemble (potentially more than two)
inputs and iteratively aligns them to the mean.  For what you want to do,
try vtkLandmarkTransform.
- Wes


-- 
Wesley D. Turner, Ph.D.
Kitware, Inc.
R&D Engineer
28 Corporate Drive
Clifton Park, NY 12065-8662
Phone: 518-371-3971 x120
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