[Insight-users] Using deformation fields when testing registration quality?

[Luis Ibanez]

Hi Motes,

I would suggest that you subtract the Known deformation field
from the deformation field that results from the registration. This
will give you a "residual" deformation field. Then you could
compute the Average Magnitude of all the vectors in these
residual deformation field.

It may also be worth to report the "largest magnitude" of that
residual deformation field.

For subtracting two deformation fields, the itkSubtractImageFilter
should do the trick (although I have not tried this filter with images
of vectors).

The computation of the average and maximum magnitude may
require you to write a customized while-loop with Iterators.

It should take about 30~40   lines of code....  :-)


Please let us know if you find any problem,


     Thanks


         Luis


-----------------------------------------------------------------------------------------
On Mon, Oct 26, 2009 at 12:11 PM, motes motes <mort.motes at gmail.com> wrote:
> I would like to measure the quality of my modfied BSplineDeformable
> transform. I have used one of the ITK examples to create a known
> deformation of the fixed image that I use as the moving image.
>
> But how do I use this known deformation in the quality measure? Since
> the deformation field is applied to the fixed image and the result is
> the moving image I don't see what benefit it does when measuring the
> quality of the registration?
>
> How are deformation fields used in this context?
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