# Difference between two displacement fields

**URL:** https://discourse.itk.org/t/difference-between-two-displacement-fields/582
**Category:** Algorithms
**Created:** [January 10, 2018, 7:48pm UTC](https://discourse.itk.org/t/difference-between-two-displacement-fields/582 "2018-01-10T19:48:38Z")
**Posts on this page:** 2
**Page:** 1

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### Author: ![Ray](https://discourse.itk.org/letter_avatar_proxy/v4/letter/r/e9a140/32.png) [@Ray](https://discourse.itk.org/u/Ray)
#### Post date: [January 10, 2018, 7:48pm UTC](https://discourse.itk.org/t/difference-between-two-displacement-fields/582/1 "2018-01-10T19:48:38Z")

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Hello!

Given two displacement fields df1 and df2, does ITK provide a way to compute the difference between the two displacement fields? i.e. || df1-df2 ||

Thanks.

-Ray

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### Author: ![matt.mccormick](https://discourse.itk.org/user_avatar/discourse.itk.org/matt.mccormick/32/7_2.png) [@matt.mccormick](https://discourse.itk.org/u/matt.mccormick)
#### Post date: [January 10, 2018, 8:03pm UTC](https://discourse.itk.org/t/difference-between-two-displacement-fields/582/2 "2018-01-10T20:03:13Z")

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Hi Ray,

Yes, this could be achieved with with

- [itk::SubtractImageFilter](https://itk.org/Doxygen/html/classitk_1_1SubtractImageFilter.html)
- [itk::VectorMagnitudeImageFilter](https://itk.org/Doxygen/html/classitk_1_1VectorMagnitudeImageFilter.html)

but, measures other than displacement magnitude may be more interesting, i.e.

- [The displacement field jacobian determinate](https://itk.org/Doxygen/html/classitk_1_1DisplacementFieldJacobianDeterminantFilter.html)
- [The strain field](https://github.com/InsightSoftwareConsortium/ITKStrain)

HTH,  
Matt