# Perimetre computation using itkShapeLabelObject

**URL:** <https://discourse.itk.org/t/perimetre-computation-using-itkshapelabelobject/1574>\
**Category:** Algorithms\
**Created:** [February 5, 2019, 4:08pm UTC](https://discourse.itk.org/t/perimetre-computation-using-itkshapelabelobject/1574 "2019-02-05T16:08:45Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![pauline](https://discourse.itk.org/letter_avatar_proxy/v4/letter/p/a88e57/32.png) [@pauline](https://discourse.itk.org/u/pauline)\
**Post date:** [February 5, 2019, 4:08pm UTC](https://discourse.itk.org/t/perimetre-computation-using-itkshapelabelobject/1574/1 "2019-02-05T16:08:46Z")

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Hi all,

I am using itkShapeLabelObject to compute the surface area of a segmented object, in a 3D image. However, I have trouble understanding the computation process from the code in ITK/Modules/Filtering/LabelMap/include/itkShapeLabelMapFilter.hxx, which is not documented anywhere else. Briefly, the algorithm goes througt the lines of the LabelObject and looks at the intercepts. I don’t understand how that gives the parameter. Does anyone understood how it works?

Thanks for your help!

Pauline

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**Author:** ![blowekamp](https://discourse.itk.org/user_avatar/discourse.itk.org/blowekamp/32/79_2.png) [@blowekamp](https://discourse.itk.org/u/blowekamp)\
**Post date:** [February 5, 2019, 4:57pm UTC](https://discourse.itk.org/t/perimetre-computation-using-itkshapelabelobject/1574/2 "2019-02-05T16:57:32Z")

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Hello,

I believe the computation is described here:  
[http://hdl.handle.net/10380/3342](http://hdl.handle.net/10380/3342)

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<div class="post-metadata">

**Author:** ![pauline](https://discourse.itk.org/letter_avatar_proxy/v4/letter/p/a88e57/32.png) [@pauline](https://discourse.itk.org/u/pauline)\
**Post date:** [February 5, 2019, 5:06pm UTC](https://discourse.itk.org/t/perimetre-computation-using-itkshapelabelobject/1574/3 "2019-02-05T17:06:10Z")

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It’s exactly what i was looking for, thank you!