# How to use SymmetricEigenAnalysisImageFilter to generate eigen vector image?

**URL:** <https://discourse.itk.org/t/how-to-use-symmetriceigenanalysisimagefilter-to-generate-eigen-vector-image/1521>\
**Category:** Algorithms\
**Created:** [January 12, 2019, 4:03pm UTC](https://discourse.itk.org/t/how-to-use-symmetriceigenanalysisimagefilter-to-generate-eigen-vector-image/1521 "2019-01-12T16:03:36Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![TaoH](https://discourse.itk.org/user_avatar/discourse.itk.org/taoh/32/1374_2.png) [@TaoH](https://discourse.itk.org/u/TaoH)\
**Post date:** [January 12, 2019, 4:03pm UTC](https://discourse.itk.org/t/how-to-use-symmetriceigenanalysisimagefilter-to-generate-eigen-vector-image/1521/1 "2019-01-12T16:03:36Z")

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I try to compute eigen vectors of the symmetric matrix corresponding to every input pixel. So, I try to add _m\_Calculator.ComputeEigenValuesAndVectors(x, eigenValues,eigenvectors)_ in _itkSymmetricEigenAnalysisImageFilter.h_. However, it does not work. The data type of eigenvectors is difficult to define for me due to the processing involved in multi-thread.

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**Author:** ![phcerdan](https://discourse.itk.org/user_avatar/discourse.itk.org/phcerdan/32/286_2.png) [@phcerdan](https://discourse.itk.org/u/phcerdan)\
**Post date:** [January 12, 2019, 6:06pm UTC](https://discourse.itk.org/t/how-to-use-symmetriceigenanalysisimagefilter-to-generate-eigen-vector-image/1521/2 "2019-01-12T18:06:26Z")

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Hi @TaoH, if you can create a minimal example (sharing the code) of what you are trying to do, there would be more chances of someone giving a hand.

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**Author:** ![dzenanz](https://discourse.itk.org/user_avatar/discourse.itk.org/dzenanz/32/1093_2.png) [@dzenanz](https://discourse.itk.org/u/dzenanz)\
**Post date:** [January 12, 2019, 6:28pm UTC](https://discourse.itk.org/t/how-to-use-symmetriceigenanalysisimagefilter-to-generate-eigen-vector-image/1521/3 "2019-01-12T18:28:41Z")

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Looking at the [unit test](https://github.com/InsightSoftwareConsortium/ITK/blob/master/Modules/Filtering/ImageIntensity/test/itkSymmetricEigenAnalysisImageFilterTest.cxx) should help you.