# Finding the Jacobian of a 3D image transform

**URL:** https://discourse.slicer.org/t/finding-the-jacobian-of-a-3d-image-transform/29018
**Category:** Support
**Tags:** transforms
**Created:** [April 20, 2023, 3:46am UTC](https://discourse.slicer.org/t/finding-the-jacobian-of-a-3d-image-transform/29018 "2023-04-20T03:46:01Z")
**Posts on this page:** 4
**Page:** 1

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### Author: ![Akor](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/akor/32/43260_2.png) [@Akor](https://discourse.slicer.org/u/Akor)
#### Post date: [April 20, 2023, 3:46am UTC](https://discourse.slicer.org/t/finding-the-jacobian-of-a-3d-image-transform/29018/1 "2023-04-20T03:46:01Z")

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Hi, so I have two 3D CT images that I’d like to register. The first being the fixed image and the second the moving image, using elastix in 3D slicer. Is there a way to have elastix output the Jacobian of the image transform? or else how do I know what transformation function is utilized so I can code for the Jacobian matrix separately.

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### Author: ![lassoan](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/lassoan/32/13_2.png) [@lassoan](https://discourse.slicer.org/u/lassoan)
#### Post date: [April 20, 2023, 3:49am UTC](https://discourse.slicer.org/t/finding-the-jacobian-of-a-3d-image-transform/29018/2 "2023-04-20T03:49:35Z")

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You can see the computed transformation matrix in Transforms module. However, Jacobian of a linear transform is not that exciting. What is your end goal?

If you want to compute strain for a warping transform then I would recommend to try [ITKStrain](https://github.com/KitwareMedical/ITKStrain) on the displacement field vector image exported in Transforms module.

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### Author: ![pieper](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/pieper/32/8_2.png) [@pieper](https://discourse.slicer.org/u/pieper)
#### Post date: [April 20, 2023, 1:29pm UTC](https://discourse.slicer.org/t/finding-the-jacobian-of-a-3d-image-transform/29018/3 "2023-04-20T13:29:22Z")

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Maybe we should incorporate ITKStrain directly in Slicer? It could be helpful as a visualization mode for nonlinear transforms.

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### Author: ![gcsharp](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/gcsharp/32/863_2.png) [@gcsharp](https://discourse.slicer.org/u/gcsharp)
#### Post date: [April 20, 2023, 4:41pm UTC](https://discourse.slicer.org/t/finding-the-jacobian-of-a-3d-image-transform/29018/4 "2023-04-20T16:41:36Z")

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@Akor If you want the Jacobian determinant rather than the matrix, you can compute that using plastimatch and then import. I’m not aware of any software that can export the Jacobian matrix.

@lassoan Thanks for the tip re: ITKStrain. Looks interesting!