# Segmentation of thin surfaces

**URL:** <https://discourse.slicer.org/t/segmentation-of-thin-surfaces/2332>\
**Category:** Support\
**Tags:** segmentation\
**Created:** [March 15, 2018, 10:24pm UTC](https://discourse.slicer.org/t/segmentation-of-thin-surfaces/2332 "2018-03-15T22:24:01Z")\
**Posts on this page:** 1\
**Showing post:** 2

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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:** [March 16, 2018, 12:30am UTC](https://discourse.slicer.org/t/segmentation-of-thin-surfaces/2332/2 "2018-03-16T00:30:32Z")

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We had very similar problem when [segmenting thin orbital bone](https://qspace.library.queensu.ca/bitstream/handle/1974/15290/Ibrahim_Amani_201612_MSc.pdf?sequence=2&isAllowed=y). Couple of things that helped:

- Crop and resample your volume to make the structures that you want to segment at least 4-5 voxel wide. Otherwise all the region-growing based method will fail, as due to random noise a few voxels may be missed and your structure may break to parts.
- Apply filtering, which enhances thin structures. We have found that unsharp masking helped.
- If the structure that you need to represent is a surface then instead of a volumetric representation, you may try to reconstruct a surface from points. See this [complete example](https://gist.github.com/lassoan/74b5efb699b1c9d3a6ef76d98c77b697) that works in Slicer as is, See also these additional VTK examples: [Poisson surface reconstruction](https://lorensen.github.io/VTKExamples/site/Cxx/Points/PoissonExtractSurface/), [comparison of 3 surface reconstruction methods that are available in VTK](https://lorensen.github.io/VTKExamples/site/Cxx/Points/CompareExtractSurface/). If this approach works well then let me know and I can make a segment editor effect from it.
- You may paint the structure manually on a couple of (non-neighbor) slices and use `Fill between slices` effect to create a complete segmentation out of it.

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