# DRR image

**URL:** https://discourse.itk.org/t/drr-image/4638
**Category:** Uncategorized
**Created:** [December 5, 2021, 10:32am UTC](https://discourse.itk.org/t/drr-image/4638 "2021-12-05T10:32:29Z")
**Posts on this page:** 7
**Page:** 1

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### Author: ![wangjun456](https://discourse.itk.org/user_avatar/discourse.itk.org/wangjun456/32/2409_2.png) [@wangjun456](https://discourse.itk.org/u/wangjun456)
#### Post date: [December 5, 2021, 10:32am UTC](https://discourse.itk.org/t/drr-image/4638/1 "2021-12-05T10:32:29Z")

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I use the example GetDRRSiddonJacobsRayTracing.cxx to generate DRR images. The data in the example can generate DRR images. when I used my own data, I can only generate an all black image. Does anyone know why?

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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: [December 6, 2021, 9:32pm UTC](https://discourse.itk.org/t/drr-image/4638/2 "2021-12-06T21:32:07Z")

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Without providing additional details, it is hard to help you.

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### Author: ![wangjun456](https://discourse.itk.org/user_avatar/discourse.itk.org/wangjun456/32/2409_2.png) [@wangjun456](https://discourse.itk.org/u/wangjun456)
#### Post date: [December 7, 2021, 2:26am UTC](https://discourse.itk.org/t/drr-image/4638/3 "2021-12-07T02:26:17Z")

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When I use the data in the example, I can generate DRR images  
 ![image](https://discourse.itk.org/uploads/default/original/2X/7/7c87575c7fc9b146a980e95f8930facc24cf99f8.png)  
But when I use a nii file of blood vessels, I get a DRR image

 ![image](https://discourse.itk.org/uploads/default/original/2X/9/994680cf1878f897c539f064f1b92cfdbd8b5da2.png)

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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: [December 7, 2021, 2:56pm UTC](https://discourse.itk.org/t/drr-image/4638/4 "2021-12-07T14:56:45Z")

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If you share your “nii file of blood vessels”, @simon.rit might be able to help you.

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### Author: ![wangjun456](https://discourse.itk.org/user_avatar/discourse.itk.org/wangjun456/32/2409_2.png) [@wangjun456](https://discourse.itk.org/u/wangjun456)
#### Post date: [December 7, 2021, 3:18pm UTC](https://discourse.itk.org/t/drr-image/4638/5 "2021-12-07T15:18:16Z")

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this is my nii file

 ![image](https://discourse.itk.org/uploads/default/original/2X/2/28371530a039298a57ce789e77ae2f143f8a778e.png)

[ves\_1.rar](https://discourse.itk.org/uploads/short-url/cN5IGxjG0IOhU1U2TDHWL6tPjAE.rar) (41.4 KB)

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### Author: ![simon.rit](https://discourse.itk.org/letter_avatar_proxy/v4/letter/s/f08c70/32.png) [@simon.rit](https://discourse.itk.org/u/simon.rit)
#### Post date: [December 7, 2021, 4:03pm UTC](https://discourse.itk.org/t/drr-image/4638/6 "2021-12-07T16:03:10Z")

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I’m not the developer or the maintainer of this code. I only know it because it’s been wrapped at some point in RTK. Nevertheless, compiling it for the first time, it seems to be an issue with pixel type. Using float instead of short in the code gives me a non-zero a DRR.

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### Author: ![wangjun456](https://discourse.itk.org/user_avatar/discourse.itk.org/wangjun456/32/2409_2.png) [@wangjun456](https://discourse.itk.org/u/wangjun456)
#### Post date: [December 8, 2021, 3:18am UTC](https://discourse.itk.org/t/drr-image/4638/7 "2021-12-08T03:18:13Z")

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Thank you for your reply. The problem is solved. It’s really a pixel problem