# Inverse of BSpline transform

**URL:** https://discourse.itk.org/t/inverse-of-bspline-transform/496
**Category:** Beginner Questions
**Created:** [December 10, 2017, 10:26pm UTC](https://discourse.itk.org/t/inverse-of-bspline-transform/496 "2017-12-10T22:26:53Z")
**Posts on this page:** 1
**Showing post:** 2

<div class="post-metadata">

### Author: ![fbudin](https://discourse.itk.org/user_avatar/discourse.itk.org/fbudin/32/14_2.png) [@fbudin](https://discourse.itk.org/u/fbudin)
#### Post date: [December 11, 2017, 3:52pm UTC](https://discourse.itk.org/t/inverse-of-bspline-transform/496/2 "2017-12-11T15:52:16Z")

</div>

Hello Ray,

The computation of the inverse of a BSpline transform is not implemented in ITK. The way to do it is (as discussed in [this mailing list thread](https://public.kitware.com/pipermail/insight-users/2008-October/027576.html)):

- Compute the deformation field corresponding to your BSpline
- Inverse your deformation field (there are multiple implementations in ITK to do this, such as [1](https://itk.org/Doxygen/html/classitk_1_1InverseDeformationFieldImageFilter.html) and [2](https://itk.org/Doxygen/html/classitk_1_1IterativeInverseDisplacementFieldImageFilter.html)). There is also a remote module that allows to compute this.
- Use this inverse transform after making sure that it has been sampled in the output image space

Hope this helps,  
Francois

---

_[View the full topic](https://discourse.itk.org/t/inverse-of-bspline-transform/496)._