<p dir="ltr">One thing to keep in mind: there is no guarantee that a displacement field is invertible. If you want invertible (+ differentiable) maps, then use diffeomorphisms. You should also check the accuracy of any inverse that you estimate to see if it maps a point back to itself. Bsplinesyn , in Itk, resolves several of these issues by using bsplines to estimate invertible maps and gives a good guarantee of the inverse's accuracy.<br>
<br><br></p>
<p dir="ltr">On Dec 10, 2013 3:07 PM, "Yago Diez" <<a href="mailto:yagodiezdonoso@gmail.com">yagodiezdonoso@gmail.com</a>> wrote:<br>
><br>
><br>
> Hi, <br>
><br>
> In one application I am needing to deform points instead of images, so I mainly have the opposites of all the deformations I need. So far, and thanks to a lot of help received here, I managed to invert deformation fields and several kinds of Rigid and Affine deformations, but so far I have had no luck with <br>
><br>
> typedef itk::BSplineDeformableTransform< double, 3, 3 > DeformableTransformType;<br>
><br>
><br>
> I have tried to use the GetInverseTransform() method (which worked for rigid and affine transformations), I can compile it but I get a segmentation fault whenever I try to use my inverted bsplines transform (the output of the deformation is NULL). I assume this comes from the fact that inverting a Bsplines transform is pretty difficult. My first question is: Is there a "quick" way to invert a Bsplines transform?<br>
><br>
> If the answer is no, I can also invert a deformation field if I can get one from the bspline tranform, so the second question is: How can I generate a deformation field from a Bsplines transform?<br>
><br>
> Thank you all once more for all your help <br>
> Yago<br>
><br>
><br>
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