# Latest

**URL:** https://discourse.itk.org/latest.md?page=5

[Latest](https://discourse.itk.org/latest.md) · [Categories](https://discourse.itk.org/categories.md) · [Tags](https://discourse.itk.org/tags.md)

**Page:** 6

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## [RTK ProjectionsReader Blank Images](https://discourse.itk.org/t/rtk-projectionsreader-blank-images/7501)

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**Author:** [@OwenM](https://discourse.itk.org/u/OwenM)\
**Replies:** 3\
**Last updated:** [April 23, 2025, 10:56pm UTC](https://discourse.itk.org/t/rtk-projectionsreader-blank-images/7501 "2025-04-23T22:56:13Z")

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Hello, Thanks in advance for any help with this issue. I have been trying to reconstruct a series of 2D CBCT projections stored in TIFFs using RTK FDK. I started with the Python first reconstruction example and got it …

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## [Why Are There Negative Voxel Values in My RTKFDK X-ray Reconstruction?](https://discourse.itk.org/t/why-are-there-negative-voxel-values-in-my-rtkfdk-x-ray-reconstruction/7498)

<div class="topic-metadata">

**Author:** [@zhangxiang](https://discourse.itk.org/u/zhangxiang)\
**Replies:** 8\
**Last updated:** [April 22, 2025, 7:45am UTC](https://discourse.itk.org/t/why-are-there-negative-voxel-values-in-my-rtkfdk-x-ray-reconstruction/7498 "2025-04-22T07:45:47Z")

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I’m working on 3D reconstruction using cone-beam X-ray projection images with the FDK algorithm in RTK (Reconstruction Toolkit). After reconstruction, I noticed that some voxel values in the output volume are negati…

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## [Improper wrapping of ImageFunction::IsInsideBuffer?](https://discourse.itk.org/t/improper-wrapping-of-imagefunction-isinsidebuffer/7495)

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**Author:** [@acoussat](https://discourse.itk.org/u/acoussat)\
**Replies:** 4\
**Last updated:** [April 16, 2025, 4:05pm UTC](https://discourse.itk.org/t/improper-wrapping-of-imagefunction-isinsidebuffer/7495 "2025-04-16T16:05:34Z")

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Dear ITK community, I am currently trying to use ImageFunction::IsInsideBuffer from within a Python script. My environment runs Python 3.12.0 and ITK 5.4.3 installed directly from Pypi. As can be seen from the documen…

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## [MetaIO documentation](https://discourse.itk.org/t/metaio-documentation/7497)

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**Author:** [@Francis](https://discourse.itk.org/u/Francis)\
**Replies:** 6\
**Last updated:** [April 16, 2025, 3:53pm UTC](https://discourse.itk.org/t/metaio-documentation/7497 "2025-04-16T15:53:25Z")

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Hi all, I have just started working with MetaIO files and was hoping to look at the ITK documentation on the subject but when I attempt to access this site: https://itk.org/Wiki/ITK/MetaIO/Documentation I get 403 Forb…

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## [similarity metrics in mono-modality registration](https://discourse.itk.org/t/similarity-metrics-in-mono-modality-registration/7493)

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**Author:** [@blue\_sky](https://discourse.itk.org/u/blue_sky)\
**Replies:** 1\
**Last updated:** [April 13, 2025, 8:48pm UTC](https://discourse.itk.org/t/similarity-metrics-in-mono-modality-registration/7493 "2025-04-13T20:48:07Z")

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Hi everyone. I am beginner in registration. The below code is part of the code related to SimpleITK Examples. It seems that this code is written for images with different modalities. But I want to register two CT images …

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## [Release cuda memory](https://discourse.itk.org/t/release-cuda-memory/7491)

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**Author:** [@langzhizhen](https://discourse.itk.org/u/langzhizhen)\
**Replies:** 2\
**Last updated:** [April 11, 2025, 12:38am UTC](https://discourse.itk.org/t/release-cuda-memory/7491 "2025-04-11T00:38:52Z")

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Hello！ I would like to ask if there is a way to manually release cuda memory in RTK. I get “ITK ERROR: CUDA ERROR: out of memony” after running function “Update()” repeatedly. I want to manually release cuda memory that…

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## [ITK 5.4.3 has been released!](https://discourse.itk.org/t/itk-5-4-3-has-been-released/7489)

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**Author:** [@matt.mccormick](https://discourse.itk.org/u/matt.mccormick)\
**Replies:** 0\
**Last updated:** [April 2, 2025, 3:27pm UTC](https://discourse.itk.org/t/itk-5-4-3-has-been-released/7489 "2025-04-02T15:27:07Z")

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We are pleased to announce the release of ITK 5.4.3, the latest maintenance update for this cross-platform, open-source toolkit supporting N-dimensional scientific image analysis with spatially-aware algorithms. :tada: …

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## [SetOptimizerWeights in parameter file in SimpleElastix](https://discourse.itk.org/t/setoptimizerweights-in-parameter-file-in-simpleelastix/7488)

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**Author:** [@Brynolf](https://discourse.itk.org/u/Brynolf)\
**Replies:** 0\
**Last updated:** [April 1, 2025, 9:37am UTC](https://discourse.itk.org/t/setoptimizerweights-in-parameter-file-in-simpleelastix/7488 "2025-04-01T09:37:53Z")

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Hello! I would like to restrict the registration to some dimensions, and found that you can use SetOptimizerWeights() in python. How can I define this if I setup my registration using a parameter file? I would like to r…

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## [Points are not transformed correctly when using BSplineTransform](https://discourse.itk.org/t/points-are-not-transformed-correctly-when-using-bsplinetransform/7483)

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**Author:** [@lukasz-migas](https://discourse.itk.org/u/lukasz-migas)\
**Replies:** 4\
**Last updated:** [March 31, 2025, 8:38am UTC](https://discourse.itk.org/t/points-are-not-transformed-correctly-when-using-bsplinetransform/7483 "2025-03-31T08:38:35Z")

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Hi, I am looking for a bit of advice (or information on where I am going wrong) with regard to applying transformation to an image and coordinating points from GeoJSON. I have a composite transform consisting of 5 tran…

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## [ForwardProjection about HU value](https://discourse.itk.org/t/forwardprojection-about-hu-value/7480)

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**Author:** [@langzhizhen](https://discourse.itk.org/u/langzhizhen)\
**Replies:** 4\
**Last updated:** [March 29, 2025, 12:41pm UTC](https://discourse.itk.org/t/forwardprojection-about-hu-value/7480 "2025-03-29T12:41:24Z")

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Hello, I have a question about the HU value. I input the data collected by CT, which is the real HU value. Is the pixel value of my reconstructed image also the real HU value? I see that the pixel values in the area outs…

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## [Closed form invertible displacement field function for testing toy problems](https://discourse.itk.org/t/closed-form-invertible-displacement-field-function-for-testing-toy-problems/7481)

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**Author:** [@reox](https://discourse.itk.org/u/reox)\
**Replies:** 3\
**Last updated:** [March 29, 2025, 9:04am UTC](https://discourse.itk.org/t/closed-form-invertible-displacement-field-function-for-testing-toy-problems/7481 "2025-03-29T09:04:35Z")

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I need to test some algorithm which does some inversion and interpolation of an image transformation using the displacement field. To get some baseline numbers, I would like to test it on a displacement field transforma…

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## [Cannot compile ITK with Python wrappings on Fedora 41 with gcc 14.2.1](https://discourse.itk.org/t/cannot-compile-itk-with-python-wrappings-on-fedora-41-with-gcc-14-2-1/7436)

<div class="topic-metadata">

**Author:** [@acoussat](https://discourse.itk.org/u/acoussat)\
**Replies:** 5\
**Last updated:** [March 28, 2025, 7:15pm UTC](https://discourse.itk.org/t/cannot-compile-itk-with-python-wrappings-on-fedora-41-with-gcc-14-2-1/7436 "2025-03-28T19:15:50Z")

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Dear ITK community, I am trying to compile ITK with Python wrappings locally on my machine. I run Fedora Linux 41 with GCC version 14.2.1. I simply run cmake -DITK\_WRAP\_PYTHON=ON ../ITK, where ../ITK is the path to ITK…

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## [Get \`numpy\` to \`SimpleITK\` data type mapping](https://discourse.itk.org/t/get-numpy-to-simpleitk-data-type-mapping/7479)

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**Author:** [@jhlegarreta](https://discourse.itk.org/u/jhlegarreta)\
**Replies:** 13\
**Last updated:** [March 27, 2025, 4:04pm UTC](https://discourse.itk.org/t/get-numpy-to-simpleitk-data-type-mapping/7479 "2025-03-27T16:04:28Z")

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Hi, is there a way to get the mapping of numpy data types to the SimpleITK data types? I have seen this, but it is a method variable, and it requires an input image. I am wondering whether I cant get the SimpleITK ty…

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## [Unexpected Behaviour in MultiStartOptimizerv4](https://discourse.itk.org/t/unexpected-behaviour-in-multistartoptimizerv4/7466)

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**Author:** [@spinicist](https://discourse.itk.org/u/spinicist)\
**Replies:** 15\
**Last updated:** [March 18, 2025, 7:12pm UTC](https://discourse.itk.org/t/unexpected-behaviour-in-multistartoptimizerv4/7466 "2025-03-18T19:12:57Z")

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Hello, I’m trying to use the MultiStartOptimizerv4. My current code is here: riesling/cxx/riesling/merlin.cpp at merlin2 · spinicist/riesling · GitHub, apologies it is a little messy at the moment. The results of the lo…

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## [Cmake issue with minc](https://discourse.itk.org/t/cmake-issue-with-minc/6496)

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**Author:** [@mborish](https://discourse.itk.org/u/mborish)\
**Replies:** 3\
**Last updated:** [March 18, 2025, 5:47pm UTC](https://discourse.itk.org/t/cmake-issue-with-minc/6496 "2025-03-18T17:47:54Z")

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Hello, I’ve recently followed the instructions on ITK’s page to install it via vcpkg. I’ve included the necessary commands: find\_package(ITK REQUIRED) and ${ITK\_LIBRARIES} in my target link. However, I get a linking er…

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## [Bone being moved during deformable registration](https://discourse.itk.org/t/bone-being-moved-during-deformable-registration/7467)

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**Author:** [@CrownMella](https://discourse.itk.org/u/CrownMella)\
**Replies:** 0\
**Last updated:** [March 18, 2025, 4:12pm UTC](https://discourse.itk.org/t/bone-being-moved-during-deformable-registration/7467 "2025-03-18T16:12:05Z")

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Hi, I am currently using diffeomorphic demons (tried step length 0.5 and 2, included smoothupdatefield and smoothdisplacementfield) to register label maps, I noticed that even if a certain object remains stationary in b…

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## [1st Get Your Brain Straight Hackathon!](https://discourse.itk.org/t/1st-get-your-brain-straight-hackathon/4896)

<div class="topic-metadata">

**Author:** [@matt.mccormick](https://discourse.itk.org/u/matt.mccormick)\
**Replies:** 1\
**Last updated:** [March 17, 2025, 2:42pm UTC](https://discourse.itk.org/t/1st-get-your-brain-straight-hackathon/4896 "2025-03-17T14:42:38Z")

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What? The Get Your Brain Straight hackathons bring together neuroimage data generators, image registration researchers, and neurodata compute infrastructure providers for a hands-on, collaborative event. This community c…

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## [To v4 or not to v4](https://discourse.itk.org/t/to-v4-or-not-to-v4/7459)

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**Author:** [@spinicist](https://discourse.itk.org/u/spinicist)\
**Replies:** 6\
**Last updated:** [March 17, 2025, 12:30pm UTC](https://discourse.itk.org/t/to-v4-or-not-to-v4/7459 "2025-03-17T12:30:46Z")

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Hello, For a new project, are the “v4” versions of registration algorithms to be preferred over the ones without a suffix? Does the impending release of ITK 6 have any impact on this choice? I’ve been away from using IT…

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## [Undefined Behaviour in ImageToImageMetricv4](https://discourse.itk.org/t/undefined-behaviour-in-imagetoimagemetricv4/7460)

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**Author:** [@spinicist](https://discourse.itk.org/u/spinicist)\
**Replies:** 1\
**Last updated:** [March 15, 2025, 12:33am UTC](https://discourse.itk.org/t/undefined-behaviour-in-imagetoimagemetricv4/7460 "2025-03-15T00:33:21Z")

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There is a note here ITK/Modules/Registration/Metricsv4/include/itkImageToImageMetricv4.hxx at master · InsightSoftwareConsortium/ITK · GitHub that ImageToImageMetricv4 does not allocate the virtual image to save memory.…

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## [ImageRegistrationMethodv4 crashes Unexpectedly](https://discourse.itk.org/t/imageregistrationmethodv4-crashes-unexpectedly/5268)

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**Author:** [@autobuyer](https://discourse.itk.org/u/autobuyer)\
**Replies:** 1\
**Last updated:** [March 12, 2025, 4:12pm UTC](https://discourse.itk.org/t/imageregistrationmethodv4-crashes-unexpectedly/5268 "2025-03-12T16:12:01Z")

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Hello, I am relatively new ITK user and I am trying to implement affine registration in C++. After going through examples, I was able to put together a reasonable solution. However, when I run it it crashes unexpectedly…

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## [Coregistration of two rectangles using SimpleITK](https://discourse.itk.org/t/coregistration-of-two-rectangles-using-simpleitk/7449)

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**Author:** [@Andre](https://discourse.itk.org/u/Andre)\
**Replies:** 9\
**Last updated:** [March 10, 2025, 12:57pm UTC](https://discourse.itk.org/t/coregistration-of-two-rectangles-using-simpleitk/7449 "2025-03-10T12:57:27Z")

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Hello, I am trying to co-register two very simple 2D png images of rectangles (white rectangle value 256 on black (0 value) background), but struggling with getting them aligned no matter what metric, optimizer or param…

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## [ITK License Compatibility Concern with VNL](https://discourse.itk.org/t/itk-license-compatibility-concern-with-vnl/7452)

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**Author:** [@bauer-tom](https://discourse.itk.org/u/bauer-tom)\
**Replies:** 3\
**Last updated:** [March 10, 2025, 11:23am UTC](https://discourse.itk.org/t/itk-license-compatibility-concern-with-vnl/7452 "2025-03-10T11:23:57Z")

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Hello, I have noticed a potential licensing conflict in ITK related to third-party code from VNL. While ITK is distributed under the permissive Apache 2.0 license, which allows commercial use, I found that the VNL modul…

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## [Unable to Read MHD Files with metaReadImage](https://discourse.itk.org/t/unable-to-read-mhd-files-with-metareadimage/7447)

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**Author:** [@GMrrc](https://discourse.itk.org/u/GMrrc)\
**Replies:** 2\
**Last updated:** [February 28, 2025, 9:34pm UTC](https://discourse.itk.org/t/unable-to-read-mhd-files-with-metareadimage/7447 "2025-02-28T21:34:14Z")

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Hello I’m encountering issues when trying to read MHD files using the metaReadImage method from ITK-Wasm. I’ve tried multiple approaches, but I cannot successfully load an MHD/ZRAW file. Additionally, the official onlin…

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## [Build ITK Wasm not yet possible from official InsightSoftwareConsortium/ITK trunk?](https://discourse.itk.org/t/build-itk-wasm-not-yet-possible-from-official-insightsoftwareconsortium-itk-trunk/7381)

<div class="topic-metadata">

**Author:** [@Sophonet](https://discourse.itk.org/u/Sophonet)\
**Replies:** 6\
**Last updated:** [February 27, 2025, 6:48pm UTC](https://discourse.itk.org/t/build-itk-wasm-not-yet-possible-from-official-insightsoftwareconsortium-itk-trunk/7381 "2025-02-27T18:48:30Z")

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Hi all, maybe a question for @matt.mccormick: Is there a reason that compiling ITK for wasm using emscripten is not possible from the main ITK repository InsightSoftwareConsortium/ITK? There is an ITK-Wasm repository w…

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## [Real-time reconstruction](https://discourse.itk.org/t/real-time-reconstruction/7373)

<div class="topic-metadata">

**Author:** [@langzhizhen](https://discourse.itk.org/u/langzhizhen)\
**Replies:** 16\
**Last updated:** [February 27, 2025, 2:02am UTC](https://discourse.itk.org/t/real-time-reconstruction/7373 "2025-02-27T02:02:35Z")

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Hello. I am now using Parker+FDK for CBCT. But right now I’m reconstructing 200 projected images by feeding them into the code, so I have to wait until the image is captured. Now I want to simulate the process of acquisi…

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## [install error](https://discourse.itk.org/t/install-error/7414)

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**Author:** [@codeling](https://discourse.itk.org/u/codeling)\
**Replies:** 4\
**Last updated:** [February 24, 2025, 3:52pm UTC](https://discourse.itk.org/t/install-error/7414 "2025-02-24T15:52:48Z")

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In a github action for building our project (which requires ITK), I’m getting a strange error trying to install ITK 5.4: CMake Error at Modules/ThirdParty/HDF5/src/itkhdf5/hl/c++/src/cmake\_install.cmake:55 (file): fil…

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## [Truncation artifact recovery](https://discourse.itk.org/t/truncation-artifact-recovery/7435)

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**Author:** [@langzhizhen](https://discourse.itk.org/u/langzhizhen)\
**Replies:** 1\
**Last updated:** [February 22, 2025, 8:33am UTC](https://discourse.itk.org/t/truncation-artifact-recovery/7435 "2025-02-22T08:33:38Z")

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Recently, I was using FDK algorithm for CBCT, but when I used FOV, there were some truncation artifacts at the beginning and end of reconstruction results, which may be caused by insufficient data collection. Then, is th…

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## [backprojection and forwardprojection about 2D image](https://discourse.itk.org/t/backprojection-and-forwardprojection-about-2d-image/7445)

<div class="topic-metadata">

**Author:** [@langzhizhen](https://discourse.itk.org/u/langzhizhen)\
**Replies:** 1\
**Last updated:** [February 22, 2025, 8:31am UTC](https://discourse.itk.org/t/backprojection-and-forwardprojection-about-2d-image/7445 "2025-02-22T08:31:37Z")

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Hi. I want achieve NMAR algorithm recently, need to use the rtk.CudaBackProjectionImageFilter and rtk.CudaForwardProjectionImageFilter in 2 d image respectively. But there seems to be some issues with the image dimension…

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## [parameter tuning](https://discourse.itk.org/t/parameter-tuning/7442)

<div class="topic-metadata">

**Author:** [@zhangxiang](https://discourse.itk.org/u/zhangxiang)\
**Replies:** 3\
**Last updated:** [February 21, 2025, 12:45am UTC](https://discourse.itk.org/t/parameter-tuning/7442 "2025-02-21T00:45:04Z")

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How can I choose the appropriate parameters of filters, such as Hann hannY multiplier radius. When I run rtkfdk.exe with these parameter input, my CPU go to 100％, I have to close cuda acceleration. subs…

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## [Share a workflow for RTK beginners](https://discourse.itk.org/t/share-a-workflow-for-rtk-beginners/7439)

<div class="topic-metadata">

**Author:** [@zhangxiang](https://discourse.itk.org/u/zhangxiang)\
**Replies:** 0\
**Last updated:** [February 19, 2025, 6:33am UTC](https://discourse.itk.org/t/share-a-workflow-for-rtk-beginners/7439 "2025-02-19T06:33:02Z")

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This workflow can be divided into three steps: calibration, transfomation of geometric parameters, using RTK 1.calibration method1 : DLT and optional optimization on reprojection errors. If you want to understand DLT…

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