# itkLevelSetDomainMapImageFilter

**URL:** <https://discourse.itk.org/t/itklevelsetdomainmapimagefilter/3436>\
**Category:** Algorithms\
**Created:** [September 5, 2020, 12:22am UTC](https://discourse.itk.org/t/itklevelsetdomainmapimagefilter/3436 "2020-09-05T00:22:44Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![rfrank](https://discourse.itk.org/user_avatar/discourse.itk.org/rfrank/32/2977_2.png) [@rfrank](https://discourse.itk.org/u/rfrank)\
**Post date:** [September 5, 2020, 12:22am UTC](https://discourse.itk.org/t/itklevelsetdomainmapimagefilter/3436/1 "2020-09-05T00:22:44Z")

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I am using this filter in a 3D image. I am wondering if others have noticed the O(n^3) (or thereabouts) nature of this filter and if they have found a different way.

It seems to apply labels by a search across the entire output space space for each voxel in the input space, and for a large 3D image that is taking an extraordinary amount of time.

Any tips welcome.

Rick

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<div class="post-metadata">

**Author:** ![rfrank](https://discourse.itk.org/user_avatar/discourse.itk.org/rfrank/32/2977_2.png) [@rfrank](https://discourse.itk.org/u/rfrank)\
**Post date:** [September 8, 2020, 1:12am UTC](https://discourse.itk.org/t/itklevelsetdomainmapimagefilter/3436/2 "2020-09-08T01:12:01Z")

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I’m investigating this further, and can’t find any documentation ( beyond doxygen).

Does anyone know what this filter does? I’m looking at someone else’s code from over 2 years ago. It seems to block the output image into labeled segments, but I’m not sure the how and why.

Thanks

Rick