# Using a scaled down version of a volume to segment, then using this segment on original large size volumes

**URL:** <https://discourse.slicer.org/t/using-a-scaled-down-version-of-a-volume-to-segment-then-using-this-segment-on-original-large-size-volumes/30853>\
**Category:** Support\
**Tags:** segmentation\
**Created:** [July 28, 2023, 10:30am UTC](https://discourse.slicer.org/t/using-a-scaled-down-version-of-a-volume-to-segment-then-using-this-segment-on-original-large-size-volumes/30853 "2023-07-28T10:30:14Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![coco](https://avatars.discourse-cdn.com/v4/letter/c/8797f3/32.png) [@coco](https://discourse.slicer.org/u/coco)\
**Post date:** [July 28, 2023, 10:30am UTC](https://discourse.slicer.org/t/using-a-scaled-down-version-of-a-volume-to-segment-then-using-this-segment-on-original-large-size-volumes/30853/1 "2023-07-28T10:30:14Z")

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Dear all,  
I have large datasets (10 to 30GB per image) which are thus difficult to segment on original files. One solution I imagined is  
1- to use a 10X downscaled version of my images,  
2- paint “seeds” in the 14 regions I want segmented,  
3- shrink the sizes of each segment by a couple of voxels,  
4- then apply the seg.nrrd file to the original large size image after and  
5- apply a grow from seed function (and go make myself a coffee…).  
Everything works well up to step 5. Segments are matching to the new high resolution image but are somewhat fixed to low resolution settings.

 ![image](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/5/a/5a85d30ebe33c4371e69345b757575940e4db8c3.jpeg)  
Thanks for your help

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**Author:** ![coco](https://avatars.discourse-cdn.com/v4/letter/c/8797f3/32.png) [@coco](https://discourse.slicer.org/u/coco)\
**Post date:** [July 28, 2023, 10:46am UTC](https://discourse.slicer.org/t/using-a-scaled-down-version-of-a-volume-to-segment-then-using-this-segment-on-original-large-size-volumes/30853/2 "2023-07-28T10:46:15Z")

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Apologies for posting something I eventually found a solution for.  
I needed to edit the Specify Geometry option to oversampling the seg.nrrd file and increase it 10X  
I am now running grow from seed the way it is supposed to on high resolution images.  
Kind regards (and if moderators feel this is not a useful topic, feel free to delete)

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**Author:** ![pieper](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/pieper/32/8_2.png) [@pieper](https://discourse.slicer.org/u/pieper)\
**Post date:** [July 28, 2023, 2:17pm UTC](https://discourse.slicer.org/t/using-a-scaled-down-version-of-a-volume-to-segment-then-using-this-segment-on-original-large-size-volumes/30853/3 "2023-07-28T14:17:11Z")

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Thanks for posting this - yes, we definitely like to keep this kind of post in the system so that others can learn in the future.