# Select complex area for segmentation

**URL:** <https://discourse.slicer.org/t/select-complex-area-for-segmentation/39640>\
**Category:** Support\
**Tags:** segmentation\
**Created:** [October 10, 2024, 7:22pm UTC](https://discourse.slicer.org/t/select-complex-area-for-segmentation/39640 "2024-10-10T19:22:32Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Thomas\_Bourdeau](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/thomas_bourdeau/32/78197_2.png) [@Thomas\_Bourdeau](https://discourse.slicer.org/u/Thomas_Bourdeau)\
**Post date:** [October 10, 2024, 7:22pm UTC](https://discourse.slicer.org/t/select-complex-area-for-segmentation/39640/1 "2024-10-10T19:22:32Z")

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Hello Everyone,

I hope this message will reach someone who can help me.

I am doing micro CT for space material application. I am looking for a way to only process segmentation in a specific area. The objective is to measure and determine the porosity (which appear in black) inside a printing object. However, during the segmentation process, even the background is calculated as it is in black (as the porosity). Normally one slice is uploaded.

Do you have any solution to only process the segmentation on the specific aera

Thanks a lot to any person who will read and maybe can help me.

Thomas

 ![cropped cropped C50_Tamb_4mm_noz_8mm_Rec0001](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/8/8/88e66398a2d3a895a10ab7fef0eb6c30b8c870d6.jpeg)

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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:** [October 11, 2024, 1:12pm UTC](https://discourse.slicer.org/t/select-complex-area-for-segmentation/39640/2 "2024-10-11T13:12:00Z")

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You can use the Threshold effect to segment all dark area and then use the Islands effect’s “Remove selected island” tool to remove the large dark background region.