# Missing module: Hausdorff distances, Dice similarity metrics

**URL:** <https://discourse.slicer.org/t/missing-module-hausdorff-distances-dice-similarity-metrics/22159>\
**Category:** Support\
**Tags:** registration, segmentation, extensions-manager\
**Created:** [February 24, 2022, 3:27pm UTC](https://discourse.slicer.org/t/missing-module-hausdorff-distances-dice-similarity-metrics/22159 "2022-02-24T15:27:38Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![Young\_Wang](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/young_wang/32/13926_2.png) [@Young\_Wang](https://discourse.slicer.org/u/Young_Wang)\
**Post date:** [February 24, 2022, 3:27pm UTC](https://discourse.slicer.org/t/missing-module-hausdorff-distances-dice-similarity-metrics/22159/1 "2022-02-24T15:27:38Z")

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Hi there, I’m tyring to calculate the Hausdorff distances, Dice similarity metrics to quantify registration results. However I noticed that [SegmentComparison](https://www.slicer.org/wiki/Documentation/Nightly/Modules/SegmentComparison) module here is missing. I wonder is there an alternative or replacement for this module?

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**Author:** ![cpinter](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/cpinter/32/7995_2.png) [@cpinter](https://discourse.slicer.org/u/cpinter)\
**Post date:** [February 25, 2022, 9:36am UTC](https://discourse.slicer.org/t/missing-module-hausdorff-distances-dice-similarity-metrics/22159/2 "2022-02-25T09:36:13Z")

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You need to install the SlicerRT extension.

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**Author:** ![Young\_Wang](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/young_wang/32/13926_2.png) [@Young\_Wang](https://discourse.slicer.org/u/Young_Wang)\
**Post date:** [February 25, 2022, 12:41pm UTC](https://discourse.slicer.org/t/missing-module-hausdorff-distances-dice-similarity-metrics/22159/3 "2022-02-25T12:41:38Z")

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@cpinter thanks for getting back to me. I am using slicer version 4.13.0 revision 30643 built 2022-02-24.  
I can’t find the SlicerRT extension in the extension manager.

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**Author:** ![Young\_Wang](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/young_wang/32/13926_2.png) [@Young\_Wang](https://discourse.slicer.org/u/Young_Wang)\
**Post date:** [February 25, 2022, 4:17pm UTC](https://discourse.slicer.org/t/missing-module-hausdorff-distances-dice-similarity-metrics/22159/4 "2022-02-25T16:17:48Z")

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hi @cpinter I just realized that the SlicerRT extension can only be found in the extension manager for the stable release. i.e. version 4.11.20210226 revision 29738 built 2021-02-28.

After I switched slicer to the stable release I was able to install the SlicerRT extension.

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**Author:** ![cpinter](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/cpinter/32/7995_2.png) [@cpinter](https://discourse.slicer.org/u/cpinter)\
**Post date:** [February 25, 2022, 8:23pm UTC](https://discourse.slicer.org/t/missing-module-hausdorff-distances-dice-similarity-metrics/22159/5 "2022-02-25T20:23:43Z")

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> [@Young\_Wang](#):
>
> can only be found in the extension manager for the stable release

It has failed only in the past two days on Windows and Mac. So you can download the SlicerRT extension on those platforms for the nightly that are older than two days:

> **[Download 3D Slicer](https://download.slicer.org/?offset=-3)**
>
> 3D Slicer is a free, open source software for visualization, processing, segmentation, registration, and analysis of medical, biomedical, and other 3D images and meshes; and planning and navigating image-guided procedures.