# FeatureExtractor values don't get along with reality value

**URL:** <https://discourse.slicer.org/t/featureextractor-values-dont-get-along-with-reality-value/15997>\
**Category:** Radiomics\
**Tags:** python, pyradiomics\
**Created:** [February 15, 2021, 3:54pm UTC](https://discourse.slicer.org/t/featureextractor-values-dont-get-along-with-reality-value/15997 "2021-02-15T15:54:19Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![11117](https://avatars.discourse-cdn.com/v4/letter/1/4af34b/32.png) [@11117](https://discourse.slicer.org/u/11117)\
**Post date:** [February 15, 2021, 3:54pm UTC](https://discourse.slicer.org/t/featureextractor-values-dont-get-along-with-reality-value/15997/1 "2021-02-15T15:54:19Z")

</div>

Hello everyone,

I’m trying to understand my results that I get from pyradiomics - FeatureExtractor and I have two questions:

1. I want to understand what values the extractor gets me, so I calculate manually the energy, max, min in the ROI to compare the results with pyradomics results. I didn’t get the same values. I checked this on the example in radiomics (brain) (with one label)  
my method - I upload the mask and the image to an float array with nrrd.read() and did manually calculate…for exp.- max(image[mask == 1])  
anyone can explain me why I don’t get the same values?

2. what the different between seg Extract to voxel Extract?  
how can I analyse the voxel Extract?

---

<div class="post-metadata">

**Author:** ![JoostJM](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/joostjm/32/1091_2.png) [@JoostJM](https://discourse.slicer.org/u/JoostJM)\
**Post date:** [March 9, 2021, 12:22pm UTC](https://discourse.slicer.org/t/featureextractor-values-dont-get-along-with-reality-value/15997/2 "2021-03-09T12:22:09Z")

</div>

Dubplicate to [Help in deep understanding pyRadiommics](https://discourse.slicer.org/t/help-in-deep-understanding-pyradiommics/16269)

---

<div class="post-metadata">

**Author:** ![JoostJM](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/joostjm/32/1091_2.png) [@JoostJM](https://discourse.slicer.org/u/JoostJM)\
**Post date:** [March 9, 2021, 12:22pm UTC](https://discourse.slicer.org/t/featureextractor-values-dont-get-along-with-reality-value/15997/3 "2021-03-09T12:22:21Z")

</div>