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<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">Hello Simon,<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">Glad to hear you’re still actively maintaining RTK
</span><span lang="EN-US" style="font-size:11.0pt;font-family:Wingdings;color:#1F497D;mso-fareast-language:EN-US">J</span><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">I made some tests following your advices, and everything is now working fine!<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">I had already started playing with the projections origin, but I was missing the point about the rotation convention.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">I guess the xxx.75 origin coordinates are related to the origin being at the “center” of the pixel?<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">Regards,<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">Albert
<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">De :</span></b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> Simon Rit [mailto:simon.rit@creatis.insa-lyon.fr]
<br>
<b>Envoyé :</b> jeudi 22 juin 2023 11:47<br>
<b>À :</b> Albert MURIENNE <Albert.MURIENNE@b-com.com><br>
<b>Cc :</b> rtk-users@openrtk.org<br>
<b>Objet :</b> Re: [Rtk-users] Problem reconstructing from synthetic data<o:p></o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><span lang="EN-US">Hi Albert,<o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US">Nice to hear that you are still working on CT. There are two things that must be accounted for<o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US">- there is a difference in convention for the rotation angle between gVirtualXRay and RTK,<o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US">- the projections are not centered if the origin is 0.<o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US">The following command lines work for me:<o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US" style="font-family:"Courier New"">rtksimulatedgeometry -n 360 -a -360 -o g --sdd 1000 --sid 500<br>
rtkfdk -p . -r 'projection([0-9]*).tif' -o fdk.mha --neworigin -159.75,-119.75,0 --newspacing 0.5 --nsort --submatch 1 --hardware cuda -g g</span><span lang="EN-US"><o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US">Let me know if something is unclear,<o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US">Simon<o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US"><o:p> </o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US">On Wed, Jun 21, 2023 at 10:04 AM Albert MURIENNE <</span><a href="mailto:Albert.MURIENNE@b-com.com"><span lang="EN-US">Albert.MURIENNE@b-com.com</span></a><span lang="EN-US">> wrote:<o:p></o:p></span></p>
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<p class="MsoNormal"><span lang="EN-US">Hello,<br>
<br>
I'm struggling to reconstruct properly a synthetic projection images sequence using RTK.<br>
The sequence was generated using gVirtualXRay (</span><a href="https://gvirtualxray.fpvidal.net/" target="_blank"><span lang="EN-US">https://gvirtualxray.fpvidal.net/</span></a><span lang="EN-US">) and a dragon 3D model, and represents a full 360 degrees CBCT
tomographic sequence, with a 500mm SID and 1000mm SDD, 0.5mm pixel size with a 640x480 image resolution, and without any offsets (perfect circular geometry). I tried reconstructions with the simplest FDK and SART implementations, inspired by RTK provided code
examples, using rtk::ProjectionsReader to read the images and rtk::ThreeDCircularProjectionGeometry to read the geometry, but the results are not good, and I don't really know if the problem comes from the data or from my reconstruction implementation.<br>
<br>
The images data, as well as the xml geometry I generated, are available for download at this link:<br>
<br>
</span><a href="https://filesender.renater.fr/?s=download&token=bc8f87b4-989c-46d7-8c4b-dac39a4df0e1" target="_blank"><span lang="EN-US">https://filesender.renater.fr/?s=download&token=bc8f87b4-989c-46d7-8c4b-dac39a4df0e1</span></a><span lang="EN-US"><br>
<br>
Could you help me pinpoint the origin of my problem? Does it come from the data itself?<br>
<br>
Thanks,<br>
<br>
Albert<br>
Murienne <br>
<br>
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