# 3D multi-modal medical image registration using user defined function for similarity metric computation

**URL:** <https://discourse.itk.org/t/3d-multi-modal-medical-image-registration-using-user-defined-function-for-similarity-metric-computation/5064>\
**Category:** Beginner Questions\
**Tags:** simpleitk, registration, python\
**Created:** [June 7, 2022, 10:09am UTC](https://discourse.itk.org/t/3d-multi-modal-medical-image-registration-using-user-defined-function-for-similarity-metric-computation/5064 "2022-06-07T10:09:04Z")\
**Posts on this page:** 1\
**Showing post:** 2

<div class="post-metadata">

**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:** [June 7, 2022, 12:16pm UTC](https://discourse.itk.org/t/3d-multi-modal-medical-image-registration-using-user-defined-function-for-similarity-metric-computation/5064/2 "2022-06-07T12:16:44Z")

</div>

To define your own metric, you might have to implement it in ITK and expose it in SimpleITK. @machadoL wanted to [write his own variant of mutual information](https://discourse.itk.org/t/changes-in-itk-mattes-mutual-information-metric/2353), he might update us on progress and maybe share his experience.

---

_[View the full topic](https://discourse.itk.org/t/3d-multi-modal-medical-image-registration-using-user-defined-function-for-similarity-metric-computation/5064)._