[Insight-users] Re: Registration Validation using Thin Plate Spline Warp

[Luis Ibanez]

Hi Kevin,

There are two independent problems in your email:

   1 - Does the registration Work ?
   2 - Does the visualization of the Deformation Field Work ?



About 1:

It is normal that a LevelSet deformable registration algorithm
cannot replicate the deformation induced by the KernelTransform.

There is no reason to expect that the LevelSet propagation can
be equivalent to the set of kernels that the KernetlTransform
used. You can expect, however, that a good approximation may be
achieved.


About 2:

Something is wrong on the way the deformation field is being
passed to Paraview. You should check the content of the different
components of the deformation field. For this purpose you could
use the "Calculator" in Paraview, for extracting each one of
the components and verifying they range of values.

If the deformation of the original image was corrected, then
your deformation fields was probably correct, and there is
only a problem in the process of saving the deformation field
to a file, and then loading it in ParaView.

What code are you using for writing the deformation field to a file ?



    Please let us know,


       Thanks


          Luis


----------------
Kevin Ming wrote:
> Hi,
> 
> I've created a synthetic image, deformed in the y direction according to 
> the following landmarks:
> 
> Source   Target
> x   y   z  x   y   z
> 55 43 01 55 43 01
> 30 35 01 30 35 01
> 33 56 01 33 56 01
> 
> 55 43 08 55 43 08
> 30 35 08 30 35 08
> 33 56 08 33 56 08
> 
> 55 43 30 55 44 30
> 30 35 30 30 36 30
> 33 56 30 33 57 30
> 
> But when I applied the level set deformable registration, even though 
> the output came out near-perfectly, the deformation field does not match 
> that produced from the warping at all; all the vectors/glyphs point in 
> the +/- z direction, none in the y direction.  I've not made any 
> modifications to the warping algorithm than was originally provided by 
> ITK, and I use ParaView to visualize the deformation field as per 
> described in the software guide, what could have happened?
> 
> 
> Thank you,
> Kevin