# Adaptive Histogram Equalization for 3D images- long run-time

**URL:** https://discourse.itk.org/t/adaptive-histogram-equalization-for-3d-images-long-run-time/1705
**Category:** Beginner Questions
**Created:** [March 25, 2019, 7:48pm UTC](https://discourse.itk.org/t/adaptive-histogram-equalization-for-3d-images-long-run-time/1705 "2019-03-25T19:48:33Z")
**Posts on this page:** 5
**Page:** 1

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### Author: ![Courtney\_Ambrozic](https://discourse.itk.org/user_avatar/discourse.itk.org/courtney_ambrozic/32/651_2.png) [@Courtney\_Ambrozic](https://discourse.itk.org/u/Courtney_Ambrozic)
#### Post date: [March 25, 2019, 7:48pm UTC](https://discourse.itk.org/t/adaptive-histogram-equalization-for-3d-images-long-run-time/1705/1 "2019-03-25T19:48:33Z")

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Hello,

I’m running the AdaptiveHistogramEqualizationImageFilter() on a 3D image that is 512x512x197. Currently, the run-time for this histogram equalization is about three hours. Does anyone have an idea as to why it is taking this long and/or any recommendations on how to decrease this run-time?

Thanks in advance!

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### Author: ![matt.mccormick](https://discourse.itk.org/user_avatar/discourse.itk.org/matt.mccormick/32/7_2.png) [@matt.mccormick](https://discourse.itk.org/u/matt.mccormick)
#### Post date: [March 25, 2019, 8:19pm UTC](https://discourse.itk.org/t/adaptive-histogram-equalization-for-3d-images-long-run-time/1705/2 "2019-03-25T20:19:56Z")

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Hello Courtney,

Welcome to ITK! 🌻

The size of the local window has a large impact on the AdaptiveHistogramEqualizationImageFilter run time – try reducing this.

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### Author: ![dzenanz](https://discourse.itk.org/user_avatar/discourse.itk.org/dzenanz/32/1093_2.png) [@dzenanz](https://discourse.itk.org/u/dzenanz)
#### Post date: [March 25, 2019, 9:00pm UTC](https://discourse.itk.org/t/adaptive-histogram-equalization-for-3d-images-long-run-time/1705/3 "2019-03-25T21:00:04Z")

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Also make sure you are running a `Release` build, and not a `Debug` build.

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### Author: ![Courtney\_Ambrozic](https://discourse.itk.org/user_avatar/discourse.itk.org/courtney_ambrozic/32/651_2.png) [@Courtney\_Ambrozic](https://discourse.itk.org/u/Courtney_Ambrozic)
#### Post date: [March 26, 2019, 3:31pm UTC](https://discourse.itk.org/t/adaptive-histogram-equalization-for-3d-images-long-run-time/1705/4 "2019-03-26T15:31:03Z")

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Hi Matt,

Thank you for your reply! Can the local window be controlled by the SetRadius() function?

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### Author: ![matt.mccormick](https://discourse.itk.org/user_avatar/discourse.itk.org/matt.mccormick/32/7_2.png) [@matt.mccormick](https://discourse.itk.org/u/matt.mccormick)
#### Post date: [March 26, 2019, 3:56pm UTC](https://discourse.itk.org/t/adaptive-histogram-equalization-for-3d-images-long-run-time/1705/5 "2019-03-26T15:56:57Z")

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> [@Courtney\_Ambrozic](#):
>
> Thank you for your reply! Can the local window be controlled by the SetRadius() function?

Yes, exactly :-).