[Insight-developers] [Insight-registration] vector transformation / reorientation

[Matthew McCormick (thewtex)]

On Sat, Nov 20, 2010 at 6:07 PM, Luis Ibanez <luis.ibanez at kitware.com> wrote:
>
>
> On Sat, Nov 20, 2010 at 7:00 PM, Matthew McCormick (thewtex)
> <matt at mmmccormick.com> wrote:
>>
>> >
>> > (b) Estimating the Rotational and Stress component of the
>> >       deformation field at that pixel location and use it to correct
>> >       the Vector (or covariant vector) accordingly.  This is
>> >       essentially based on the Jacobian matrix of the deformation
>> >       field, estimated at the location of the pixel.
>> >
>>
>> I have a StrainImageFilter that calculates the strain tensor from a
>> deformation field if it would be of any help.  I assume what is meant
>> by the 'Rotational and Stress component' are the same as the angles to
>> the principle strains and the principle strains.  I intend on
>> submitting this filter to the Insight Journal in the next week or two
>> after I get another paper out and the following patch gets merged:
>>
>>
>> http://review.source.kitware.com/#q,status:open+project:ITK+branch:master+topic:BUG0010725_VTKTensors3,n,z
>>
>> Matt
>
>
> Excellent !
>
> Yes,
> that what I meant by the stress component.
>
> Do you see a way of deriving as well
> the rotational component of the Jacobian  ?
>

I was thinking just using
http://www.itk.org/Doxygen320/html/classitk_1_1SymmetricEigenAnalysis.html#_details

And the eigenvectors determine the rotation, while the eigenvalues
(principle strains) determine the compression/expansion of the
components?  Correct?

Matt