# Cannot apply Threshold on ROI

**URL:** https://discourse.slicer.org/t/cannot-apply-threshold-on-roi/7269
**Category:** Support
**Tags:** segmentation, threshold
**Created:** [June 20, 2019, 9:57pm UTC](https://discourse.slicer.org/t/cannot-apply-threshold-on-roi/7269 "2019-06-20T21:57:18Z")
**Posts on this page:** 4
**Page:** 1

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### Author: ![Apex](https://avatars.discourse-cdn.com/v4/letter/a/e56c9b/32.png) [@Apex](https://discourse.slicer.org/u/Apex)
#### Post date: [June 20, 2019, 9:57pm UTC](https://discourse.slicer.org/t/cannot-apply-threshold-on-roi/7269/1 "2019-06-20T21:57:18Z")

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Operating system: Windows, Linux, and Mac  
Slicer version:4.10.2  
Expected behavior: Issue 1: **To “apply” “Threshold” on ROI**  
Issue 2: **Can apply “Threshold”, but it is automatically reduced to a smaller region when I pressed “apply”.**  
Actual behavior:  
**Issue 1:**  
Threshold:

 ![pasted%20image%200](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/f/8/f8b6c11f22434f9dac26e92fb0b2592eb92cfcc4.jpeg)  
Apply: ![pasted%20image%201](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/9/3/9320d35f1a0fd6a9aa9624b11a740c8885f732fc.jpeg)

**Issue 2**  
Threshold:

 ![pasted%20image%202](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/4/3/4346312b760b3cf5e1fd0f03fd39dff3f36860e5.png)  
Apply: ![pasted%20image%203](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/1/2/125269f16787518a073f266b85d9303a0bdfdeda.jpeg)

Though the threshold is working in the majority of cases, there are few on which it is not working.  
Can anyone help me to resolve this?  
Thank you

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<div class="post-metadata">

### 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: [June 20, 2019, 10:04pm UTC](https://discourse.slicer.org/t/cannot-apply-threshold-on-roi/7269/2 "2019-06-20T22:04:45Z")

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Preview is shown on the entire image visible in the view. When you apply the threshold, it is applied to the region specified in the segmentation node’s geometry.

Segmentation node’s geometry is defined by default by the first selected master node. If you switch master nodes, maximum extent of the segmentation will not change. You need to click on “Specify geometry” button to change the extent of the segmentation.

![image](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/f/6/f6d726ba2dc21621909757eb5448d8a4b909e595.png)

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<div class="post-metadata">

### Author: ![Apex](https://avatars.discourse-cdn.com/v4/letter/a/e56c9b/32.png) [@Apex](https://discourse.slicer.org/u/Apex)
#### Post date: [June 21, 2019, 5:57am UTC](https://discourse.slicer.org/t/cannot-apply-threshold-on-roi/7269/3 "2019-06-21T05:57:25Z")

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Thank you very much for the support. Now its working.

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<div class="post-metadata">

### Author: ![Apex](https://avatars.discourse-cdn.com/v4/letter/a/e56c9b/32.png) [@Apex](https://discourse.slicer.org/u/Apex)
#### Post date: [June 21, 2019, 10:22am UTC](https://discourse.slicer.org/t/cannot-apply-threshold-on-roi/7269/4 "2019-06-21T10:22:29Z")

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Thank you for your response