# Why does Slicer lower image quality?

**URL:** <https://discourse.slicer.org/t/why-does-slicer-lower-image-quality/12208>\
**Category:** Support\
**Created:** [June 24, 2020, 10:41pm UTC](https://discourse.slicer.org/t/why-does-slicer-lower-image-quality/12208 "2020-06-24T22:41:23Z")\
**Posts on this page:** 8\
**Page:** 1

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**Author:** ![Pablo\_Javier](https://avatars.discourse-cdn.com/v4/letter/p/f04885/32.png) [@Pablo\_Javier](https://discourse.slicer.org/u/Pablo_Javier)\
**Post date:** [June 24, 2020, 10:41pm UTC](https://discourse.slicer.org/t/why-does-slicer-lower-image-quality/12208/1 "2020-06-24T22:41:23Z")

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I´ve noticed SLICER lowers image quality ( for example DICOM or jpg images). When I compare images with other types of softwares the quality of that image is much better than with SLICER. Why does SLICER do that? Is there any way of avoiding it?

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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:** [June 24, 2020, 10:58pm UTC](https://discourse.slicer.org/t/why-does-slicer-lower-image-quality/12208/2 "2020-06-24T22:58:08Z")

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I’m afraid you will have to provide specific examples of what you mean here. We go to great lengths to preserve image quality.

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**Author:** ![Pablo\_Javier](https://avatars.discourse-cdn.com/v4/letter/p/f04885/32.png) [@Pablo\_Javier](https://discourse.slicer.org/u/Pablo_Javier)\
**Post date:** [June 26, 2020, 12:30am UTC](https://discourse.slicer.org/t/why-does-slicer-lower-image-quality/12208/3 "2020-06-26T00:30:11Z")

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For example nii images (NMR image). When I open it with Slicer and Brainstorm (Matlab), I´ve noticed that the resolution is worse in Slicer than in Brainstorm (particularly in 3D viewer).

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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:** [June 26, 2020, 12:43am UTC](https://discourse.slicer.org/t/why-does-slicer-lower-image-quality/12208/4 "2020-06-26T00:43:05Z")

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Can you provide screenshots, data, and specific instructions to reproduce?

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<div class="post-metadata">

**Author:** ![Pablo\_Javier](https://avatars.discourse-cdn.com/v4/letter/p/f04885/32.png) [@Pablo\_Javier](https://discourse.slicer.org/u/Pablo_Javier)\
**Post date:** [June 26, 2020, 9:15pm UTC](https://discourse.slicer.org/t/why-does-slicer-lower-image-quality/12208/5 "2020-06-26T21:15:54Z")

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For example a simple jpg image:

 ![cosmos-galaxies](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/7/b/7baafdcd116c62000181ca8cdadfb6856d7dd3c8.jpeg)

In Slicer (3D Viewer) looks like that:

 ![123](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/f/b/fbaaac52c903271025e069657a37ef3e84743a57.jpeg)

Low resolution affects any medical images, too.

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**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 26, 2020, 10:00pm UTC](https://discourse.slicer.org/t/why-does-slicer-lower-image-quality/12208/6 "2020-06-26T22:00:18Z")

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By default, the same image resolution is shown in 3D views as in slice views. In extreme cases this may indeed result in lower resolution displayed in 3D views, which might not be want you expect:

 ![image](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/5/8/58d094cc8d9ac601cde14800feef9bc8bf35c7ec.jpeg)

If you want to decouple 3D view’s resolution from the slice view’s then you can choose one of the “Spacing match Volumes” options in slice view visibility submenu:

 ![image](https://us1.discourse-cdn.com/flex002/uploads/slicer/original/3X/3/1/31c48789697f356cfd0506090a9aebb30daed128.jpeg)

What kind of images do you work with? How large was your slice view?

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<div class="post-metadata">

**Author:** ![Pablo\_Javier](https://avatars.discourse-cdn.com/v4/letter/p/f04885/32.png) [@Pablo\_Javier](https://discourse.slicer.org/u/Pablo_Javier)\
**Post date:** [June 27, 2020, 2:29am UTC](https://discourse.slicer.org/t/why-does-slicer-lower-image-quality/12208/7 "2020-06-27T02:29:32Z")

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Thank you! Your answer has been really helpful.  
Doctors who work with me have problems with the resolution of 3D Slicer images. That´s why I had this question.

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**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 27, 2020, 6:27am UTC](https://discourse.slicer.org/t/why-does-slicer-lower-image-quality/12208/8 "2020-06-27T06:27:19Z")

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No problem, feel free to ask whenever you have any questions.