# what algorithm is 3Dslicer's Add Scalar Volumes module based on for image fusion?

**URL:** <https://discourse.slicer.org/t/what-algorithm-is-3dslicers-add-scalar-volumes-module-based-on-for-image-fusion/28888>\
**Category:** Support\
**Tags:** registration\
**Created:** [April 13, 2023, 2:08pm UTC](https://discourse.slicer.org/t/what-algorithm-is-3dslicers-add-scalar-volumes-module-based-on-for-image-fusion/28888 "2023-04-13T14:08:02Z")\
**Posts on this page:** 5\
**Page:** 1

<div class="post-metadata">

**Author:** ![ending](https://avatars.discourse-cdn.com/v4/letter/e/53a042/32.png) [@ending](https://discourse.slicer.org/u/ending)\
**Post date:** [April 13, 2023, 2:08pm UTC](https://discourse.slicer.org/t/what-algorithm-is-3dslicers-add-scalar-volumes-module-based-on-for-image-fusion/28888/1 "2023-04-13T14:08:03Z")

</div>

I have a question for everyone  
what algorithm is 3Dslicer’s Add Scalar Volumes module based on for image fusion?

---

<div class="post-metadata">

**Author:** ![Sam\_Horvath](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/sam_horvath/32/3092_2.png) [@Sam\_Horvath](https://discourse.slicer.org/u/Sam_Horvath)\
**Post date:** [April 13, 2023, 2:12pm UTC](https://discourse.slicer.org/t/what-algorithm-is-3dslicers-add-scalar-volumes-module-based-on-for-image-fusion/28888/2 "2023-04-13T14:12:51Z")

</div>

The code for the module can be found here:  
[Slicer/AddScalarVolumes.cxx at fd7b4f3cceba976aabeb2e1cdda9ecc685fc0c64 · Slicer/Slicer · GitHub](https://github.com/Slicer/Slicer/blob/fd7b4f3cceba976aabeb2e1cdda9ecc685fc0c64/Modules/CLI/AddScalarVolumes/AddScalarVolumes.cxx#L34).

It uses an ITK filter to add the images. The specific ITK filter used is the [ConstrainedValueAdditionImageFilter](https://itk.org/Doxygen/html/classitk_1_1ConstrainedValueAdditionImageFilter.html).

---

<div class="post-metadata">

**Author:** ![ending](https://avatars.discourse-cdn.com/v4/letter/e/53a042/32.png) [@ending](https://discourse.slicer.org/u/ending)\
**Post date:** [April 13, 2023, 2:18pm UTC](https://discourse.slicer.org/t/what-algorithm-is-3dslicers-add-scalar-volumes-module-based-on-for-image-fusion/28888/3 "2023-04-13T14:18:32Z")

</div>

Thank you for your timely answer, your answer solved the problem I encountered during the research.  
In addition, can I extract features in the image of PET and CT fusion, is this feasible in research?  
Looking forward to your reply！

---

<div class="post-metadata">

**Author:** ![Sam\_Horvath](https://sea2.discourse-cdn.com/flex002/user_avatar/discourse.slicer.org/sam_horvath/32/3092_2.png) [@Sam\_Horvath](https://discourse.slicer.org/u/Sam_Horvath)\
**Post date:** [April 13, 2023, 2:30pm UTC](https://discourse.slicer.org/t/what-algorithm-is-3dslicers-add-scalar-volumes-module-based-on-for-image-fusion/28888/4 "2023-04-13T14:30:45Z")

</div>

For PET/CT feature extraction, I think the starting point would by [SlicerRadiomics / pyradiomics](https://github.com/AIM-Harvard/SlicerRadiomics). It should be available in the current preview build (except for macOS).

---

<div class="post-metadata">

**Author:** ![ending](https://avatars.discourse-cdn.com/v4/letter/e/53a042/32.png) [@ending](https://discourse.slicer.org/u/ending)\
**Post date:** [April 13, 2023, 2:34pm UTC](https://discourse.slicer.org/t/what-algorithm-is-3dslicers-add-scalar-volumes-module-based-on-for-image-fusion/28888/5 "2023-04-13T14:34:18Z")

</div>

Thanks！  
sorry, maybe I didn’t make the question clear, I mean can I extract features separately in the three images of PET, CT, PET/CT fusion images?  
Looking forward to your reply！