[Insight-users] Rigid3DTransform error Attempting to set a non-orthogonal rotation matrix

[Matthias Keil]

Hello,

with regards to this e-mail to the mailing list which unfortunately did 
not get any feedback:

http://www.nabble.com/funning-observation-regarding-SetMatrix%28%29-in-VersorRigid3DTransform-class--tp20409801p20409801.html

I am writing to the mailing list hoping to get some more insight into the problem.

Using Rigid3DTransform and the Amoeba optimizer for registration of 2 volumes (one was manually rotated by 5 degrees around the x axis) seems to be quite challenging to me. Unfortunately I can't initialize my registration in a way which makes it compute any iterations. I do get the error "Attempting to set a non-orthogonal rotation matrix" mentioned in the subject everytime. As pinpress guessed right, there is a test for the identity matrix.
> My guess is that in ITK library somewhere, there is a check (e.g., to check
> if determinant of the matrix is exactly 1, because it is a "rigid"
> transform), but the tolerance is not set properly which caused the problem
> that I experience.
This test is implemented in itkRigid3DTransform.txx line 77.

I am using the following parameter values for Rigid3DTransform:
- first 9 rotation parameters are set to 0.1
- the three translation parameters are set to 0.001

And the simplex delta parameter values for the optimizer:
- first 9 values set to 5
- the last 3 values set to 0 (as there is no translation)

My question is now as pinpress already asked
> However, is such checking necessary?
Thanks in advance for any help,
Matthias

-- 
| Dipl.-Ing. Matthias Keil
|
| Fraunhofer Institute for Computer Graphics (IGD)
| Cognitive Computing & Medical Imaging
| Fraunhoferstraße 5, 64283 Darmstadt, Germany
|
| phone  : +49 6151 155 212
| fax    : +49 6151 155 480
| mobile : +49 173 5709746
| e-mail : matthias.keil at igd.fraunhofer.de
| skype  : matthias.keil.office
| web    : http://www.igd.fraunhofer.de/~makeil

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.itk.org/pipermail/insight-users/attachments/20090212/8969f789/attachment.htm>