# ITK functions need more documentation

**URL:** <https://discourse.itk.org/t/itk-functions-need-more-documentation/5817>\
**Category:** Beginner Questions\
**Tags:** bspline, simpleitk, registration\
**Created:** [March 21, 2023, 2:33pm UTC](https://discourse.itk.org/t/itk-functions-need-more-documentation/5817 "2023-03-21T14:33:52Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![imranmuet](https://discourse.itk.org/letter_avatar_proxy/v4/letter/i/43a26b/32.png) [@imranmuet](https://discourse.itk.org/u/imranmuet)\
**Post date:** [March 21, 2023, 2:33pm UTC](https://discourse.itk.org/t/itk-functions-need-more-documentation/5817/1 "2023-03-21T14:33:52Z")

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Dear All:

I am new in this field and implementing a registration code. But when I search Simple ITK documentation, I find it unfriendly for complete beginners. For example, when I search online to understand the code `sitk.BSplineTransformInitializer(image1 = fixed\_slice\_img, transformDomainMeshSize = (6,6), order=3)', I don’t get any help. So my question is where I can find proper documentation to know about the parameters (transformDomainMeshSize, order, etc.). What are these values and how can we specify their values. Please elaborate with detail. Thanking you in anticipation.

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**Author:** ![zivy](https://discourse.itk.org/user_avatar/discourse.itk.org/zivy/32/1726_2.png) [@zivy](https://discourse.itk.org/u/zivy)\
**Post date:** [March 21, 2023, 2:50pm UTC](https://discourse.itk.org/t/itk-functions-need-more-documentation/5817/2 "2023-03-21T14:50:38Z")

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Hello @imranmuet,

To learn SimpleITK, see the documentation on [read-the-docs](https://simpleitk.readthedocs.io/en/master/index.html), [registration in particular](https://simpleitk.readthedocs.io/en/master/registrationOverview.html) and the [API doxygen documentation](https://simpleitk.org/doxygen/v2_2/html/).

Additionally we recommend going through the [online tutorial](https://simpleitk.org/TUTORIAL/), and possibly the [notebook repository](https://github.com/InsightSoftwareConsortium/SimpleITK-Notebooks), specifically the 6\* series of notebooks that deal with registration.

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**Author:** ![Vidya](https://discourse.itk.org/user_avatar/discourse.itk.org/vidya/32/3986_2.png) [@Vidya](https://discourse.itk.org/u/Vidya)\
**Post date:** [April 3, 2024, 12:06pm UTC](https://discourse.itk.org/t/itk-functions-need-more-documentation/5817/3 "2024-04-03T12:06:07Z")

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Hi @zivy ,  
Is there any similar tutorials or documentation available for ITK module also?  
I am new to ITK. And I am trying to register two images and i am pretty much stuck because i have no idea how registration framework updates the transform. And i am not sure how to get the intermediate transform to verify the updation.

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**Author:** ![zivy](https://discourse.itk.org/user_avatar/discourse.itk.org/zivy/32/1726_2.png) [@zivy](https://discourse.itk.org/u/zivy)\
**Post date:** [April 3, 2024, 12:41pm UTC](https://discourse.itk.org/t/itk-functions-need-more-documentation/5817/4 "2024-04-03T12:41:57Z")

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Hello @Vidya,

Beyond the SimpleITK documentation listed above there is the [ITK book](https://itk.org/ItkSoftwareGuide.pdf) which is the authoritative documentation for all things ITK.

The only caveat is that the code examples in the book are in C++, so the syntax may not be familiar to all. The [ITK examples](https://examples.itk.org/src/) include both C++ and Python so possibly a good source if you want to understand how to translate C++ to Python (you can obviously try an LLM, Gemini, chatGPT etc., to get some form of translation).