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<div class="moz-cite-prefix">On 28.08.20 14:13, Simon Rit wrote:<br>
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cite="mid:CAF0oig2ND0AuBt-Fr6ASQ-HiK+WDGcrWDN8V5eBYV0QUyF+g3g@mail.gmail.com">
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<div>Thanks for the illustration. Maybe the detector is not
oriented as intended by RTK? If you look at the first drawing
of the <a href="http://www.openrtk.org/Doxygen/DocGeo3D.html"
moz-do-not-send="true">geometry doc</a>, I would question
the direction of the vector v. You can probably just flip it
to put it in the right direction? e.g. with</div>
<div><span style="font-family:monospace">rtkfdk -p . -r
^proj.mha$ -g direct.xml --spacing 0.5 -d 300 --hardware
cuda -o fdk.mha --newdirection 1,0,0,0,-1,0,0,0,1
--neworigin -140,151.6,0</span></div>
<div>which comes down to flipping the y axis after
reconstruction without the last two options. I think that the
RTK coordinate system becomes indirect if you flip this v axis
which is probably ignored by your visualization tool. I admit
I realized only recently that I often reconstruct data which
are like this.<br>
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<div>I hope I'm clear, if not that's probably because I don't
master so well all this...</div>
<div>Simon<br>
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<div dir="ltr" class="gmail_attr">On Fri, Aug 28, 2020 at 1:23
PM Vincent Libertiaux <<a href="mailto:vl@xris.eu"
moz-do-not-send="true">vl@xris.eu</a>> wrote:<br>
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<div>Hi Simon,</div>
<div><br>
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<div>I am afraid I was no clear enough. Please find a
picture of the real object and the reko at that link:</div>
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<div><a
href="https://www.dropbox.com/sh/ul0oy9kv3us4ey7/AABQ5Y4R1PR-jcRawGFKOUK4a?dl=0"
target="_blank" moz-do-not-send="true">https://www.dropbox.com/sh/ul0oy9kv3us4ey7/AABQ5Y4R1PR-jcRawGFKOUK4a?dl=0</a></div>
<div><br>
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<div>So you can see that on the part, the serial number is
on the "head" side while it is on the "tail" side on the
reconstruction, using the "direct" geometry. That is what
I call the mirror image. The rotation axis is along the
vertical direction of the image. I could easily reorder
the reconstructed slice to get it in the right
orientation, but I was wondering where the issue comes
from.</div>
<div><br>
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<div>Best regards,</div>
<div>Vincent<br>
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<div><br>
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<div>On 28.08.20 12:13, Simon Rit wrote:<br>
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<div dir="ltr">Mirror in which direction? Depending on the
direction, it can also be a 180° offset of the angle. If
it reconstructs well, I would assume that the direct
direction is the correct one but there is something else
you need to understand...<br>
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<br>
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<div dir="ltr" class="gmail_attr">On Fri, Aug 28, 2020
at 10:44 AM Vincent Libertiaux <<a
href="mailto:vl@xris.eu" target="_blank"
moz-do-not-send="true">vl@xris.eu</a>> wrote:<br>
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0px 0.8ex;border-left:1px solid
rgb(204,204,204);padding-left:1ex">
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<p>Hi Simon,</p>
<p>thank you for testing my dataset.</p>
<p>I get the same results you describe and I am
quite happy with the first result. However, the
reconstructed volume is a "mirror" view of the
real object, and my guess was that the rotating
plate was going in the opposite direction assumed
by rtk. Is it the wrong assumption? <br>
</p>
<p>Thank you again for your help,</p>
<p>best regards,</p>
<p>Vincent<br>
</p>
<p><br>
</p>
<div>Thanks for the dataset. When I run</div>
<div><span style="font-family:monospace"> rtkfdk -p
. -r ^proj.mha$ -g direct.xml --spacing 0.5 -d
300 --hardware cuda -o fdk.mha</span></div>
<div>The result looks good to me. Obviously, when I
run</div>
<div><span style="font-family:monospace"> rtkfdk -p
. -r ^proj.mha$ -g inverse.xml --spacing 0.5 -d
300 --hardware cuda -o fdk.mha</span></div>
<div>the result is bad since the correct rotation
direction seems to be the direct one. Did you
expect the second line to produce the correct
result? Or is the first line not producing a good
enough result in your opinion?</div>
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<p>Hi Simon,</p>
<p>thanks for the explanation. I'll have a go later today or
Monday, but I will definitely let you know what was the result.</p>
<p><br>
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<p>Have a nice week end,</p>
<p>Vincent<br>
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