# Window Level Manual Min/Max

**URL:** <https://discourse.slicer.org/t/window-level-manual-min-max/10665>\
**Category:** Support\
**Created:** [March 12, 2020, 8:35pm UTC](https://discourse.slicer.org/t/window-level-manual-min-max/10665 "2020-03-12T20:35:52Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Anonymous2](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/anonymous2/32/5985_2.png) [@Anonymous2](https://discourse.slicer.org/u/Anonymous2)\
**Post date:** [March 12, 2020, 8:35pm UTC](https://discourse.slicer.org/t/window-level-manual-min-max/10665/1 "2020-03-12T20:35:53Z")

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Hello,

I am trying to understand how the manual min/max window level and threshold in the volumes tab works. I need to be able to convert back from pixel intensity to Hounsfield units. I use screen capture to obtain a png image and I save the nifti data to know the Hounsfield units. When I plot (using Matlab) the relationship between the Hounsfield units and pixel intensity, I don’t see any relationship to the window level. If there is a simple way to convert from png back to Hounsfield units, please let me know.

Thanks!

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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:** [March 12, 2020, 10:32pm UTC](https://discourse.slicer.org/t/window-level-manual-min-max/10665/2 "2020-03-12T22:32:00Z")

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Nifti is developed for functional MRI imaging. Try to use nrrd file format instead. Window/Level adjustment is a simple linear mapping of the selected window to 8-bit (0-255) displayable intensity range.