# elastix 5.3.0 released!

**URL:** https://discourse.itk.org/t/elastix-5-3-0-released/7707
**Category:** Announcements
**Tags:** registration
**Created:** [February 6, 2026, 2:05pm UTC](https://discourse.itk.org/t/elastix-5-3-0-released/7707 "2026-02-06T14:05:51Z")
**Posts on this page:** 3
**Page:** 1

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### Author: ![Niels\_Dekker](https://discourse.itk.org/letter_avatar_proxy/v4/letter/n/9d8465/32.png) [@Niels\_Dekker](https://discourse.itk.org/u/Niels_Dekker)
#### Post date: [February 6, 2026, 2:05pm UTC](https://discourse.itk.org/t/elastix-5-3-0-released/7707/1 "2026-02-06T14:05:52Z")

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🎉 I’m very pleased to announce that we have just released version 5.3.0 of our image registration toolbox `elastix`, at [https://github.com/SuperElastix/elastix/releases](https://github.com/SuperElastix/elastix/releases)

Binaries of elastix executables are provided for Windows, MacOS (ARM) and Ubuntu. But of course, you can also build them yourself, using ITK \>= 5.4.1.

A new [ITKElastix](https://github.com/InsightSoftwareConsortium/ITKElastix) Python package based on elastix 5.3.0 is intended to be released next week, hopefully.

elastix 5.3.0 includes the following improvements:

- Added a new metric component: IMPACT (Image Metric with Pretrained model-Agnostic Comparison for Transmodality registration), by Valentin Boussot et al.
  - Reference: “IMPACT : A Generic Semantic Loss for Multimodal Image Registration”, Valentin Boussot et al, [arXiv:2503.24121](https://arxiv.org/abs/2503.24121)
  - In order to use this metric, download LibTorch and enable CMake option `USE_ImpactMetric`. More information: [GitHub - vboussot/ImpactLoss: IMPACT Reg: A Generic Semantic Loss for Multimodal Image Registration](https://github.com/vboussot/ImpactLoss)

- Supported the [TOML](https://toml.io) format for registration parameter files and transform parameter files
  - As alternative to the “legacy” elastix specific text file format

- Supported fixed width notation for the elastix parameter `ResultImagePixelType`
  - Supported parameter values: “int8”, “int16”, “int32”, “int64”, “uint8”, “uint16”, “uint32”, “uint64”, “float32”, “float64”

- Supported registering a 3D slice on a 3D volume
  - The default pyramid (“FixedSmoothingImagePyramid”, “MovingSmoothingImagePyramid”) now accepts 3D images that have a thickness of 1 pixel
  - Inspired by forum.image.sc topic [Elastix questions related to 2D =\> 3D registration](https://forum.image.sc/t/elastix-questions-related-to-2d-3d-registration/117821), started by Christian Tischer

- Improved transformix command-line option “-def” for VTK files
  - When the input file is a binary VTK file, the output file is now also a binary VTK file (rather than an ASCII file)
  - When the input file is a VTK file of 32-bit floating points, the output file is now also a VTK file of 32-bit floating points (rather than 64-bit floating points)
  - Inspired by pull request [ENH: Support for binary point file (.bin) reading and writing by ChristophKirst · Pull Request #943 · SuperElastix/elastix · GitHub](https://github.com/SuperElastix/elastix/pull/943)

- Library enhancements:
  - Added `SetFixedPoints` and `SetMovingPoints` member functions to `ElastixRegistrationMethod`
    - Supported specifying the input points for “CorrespondingPointsEuclideanDistanceMetric”

  - Made random number generation used by samplers deterministic, even when running registrations multithreaded
    - Aims to address [Deterministic multithreading usage of itkMersenneTwisterRandomVariate… by michalmeszaroswork · Pull Request #5287 · InsightSoftwareConsortium/ITK · GitHub](https://github.com/InsightSoftwareConsortium/ITK/pull/5287)

For all the details, please check [https://github.com/SuperElastix/elastix/releases](https://github.com/SuperElastix/elastix/releases)

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### Author: ![Niels\_Dekker](https://discourse.itk.org/letter_avatar_proxy/v4/letter/n/9d8465/32.png) [@Niels\_Dekker](https://discourse.itk.org/u/Niels_Dekker)
#### Post date: [March 30, 2026, 12:00pm UTC](https://discourse.itk.org/t/elastix-5-3-0-released/7707/2 "2026-03-30T12:00:20Z")

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Last week we released an update: elastix 5.3.1! Again, please check [Releases · SuperElastix/elastix · GitHub](https://github.com/SuperElastix/elastix/releases) ! Most important improvements of this elastix 5.3.1:

- For Windows users: With this release, the executables (`elastix.exe` and `transformix.exe`) fully support Unicode (utf-8) file path names for registration parameter files and transform parameter files. A big thank you to Bernhard Fröhler (@codeling)!
- The IMPACT metric component that was introduced with elastix 5.3.0 is now loaded as a plugin, by means of “lazy loading”, allowing anyone to use it without having to rebuild elastix. Another big thank you to Valentin Boussot!
- For users of Linux and MacOS: The executables (`elastix` and `transformix`) now have a relative path to the directory of the third party library that we are using added to its `RPATH`. So now it is no longer necessary for users to set their `LD_LIBRARY_PATH`. The extra versioned “.1” library files were removed.
- A small performance improvement was achieved for the metrics (specifically “DistancePreservingRigidityPenalty” and “TransformRigidityPenalty”) and two transforms (“BSplineTransformWithDiffusion” “MultiBSplineTransformWithNormal”).
- Improved error handling for ParameterObject: it now throws an exception when the specified index or parameter name is not there.

This latest update is also wrapped by [ITKElastix](https://github.com/InsightSoftwareConsortium/ITKElastix/) version 0.25.2, which was released last week as well, thanks to @matt.mccormick. (Python package [itk-elastix](https://pypi.org/project/itk-elastix)).

I think a SimpleITK/Elastix upgrade to elastix 5.3.1 is also underway, maybe @blowekamp can confirm 😃

For Debian, elastix 5.3.1 is made available at [Debian -- Details of source package elastix in sid](https://packages.debian.org/source/sid/elastix) , thanks @SteveRobbins!

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### Author: ![blowekamp](https://discourse.itk.org/user_avatar/discourse.itk.org/blowekamp/32/79_2.png) [@blowekamp](https://discourse.itk.org/u/blowekamp)
#### Post date: [April 6, 2026, 1:00pm UTC](https://discourse.itk.org/t/elastix-5-3-0-released/7707/3 "2026-04-06T13:00:03Z")

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> [@Niels\_Dekker](#):
>
> I think a SimpleITK/Elastix upgrade to elastix 5.3.1 is also underway, maybe @blowekamp can confirm 😃

SimpleITK with Elastix 5.3.1 has been incorporated in the current “main” development branch of SimpleITK and is available it you build it from the source code currently.