On 28.08.20 14:13, Simon Rit wrote:
Thanks for the illustration. Maybe the detector is not oriented as
intended by RTK? If you look at the first drawing of the geometry doc
<http://www.openrtk.org/Doxygen/DocGeo3D.html>, 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
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
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.
I hope I'm clear, if not that's probably because I don't master so
well all this...
Simon
On Fri, Aug 28, 2020 at 1:23 PM Vincent Libertiaux <[email protected]
<mailto:[email protected]>> wrote:
Hi Simon,
I am afraid I was no clear enough. Please find a picture of the
real object and the reko at that link:
https://www.dropbox.com/sh/ul0oy9kv3us4ey7/AABQ5Y4R1PR-jcRawGFKOUK4a?dl=0
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.
Best regards,
Vincent
On 28.08.20 12:13, Simon Rit wrote:
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...
On Fri, Aug 28, 2020 at 10:44 AM Vincent Libertiaux <[email protected]
<mailto:[email protected]>> wrote:
Hi Simon,
thank you for testing my dataset.
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?
Thank you again for your help,
best regards,
Vincent
Thanks for the dataset. When I run
rtkfdk -p . -r ^proj.mha$ -g direct.xml --spacing 0.5 -d
300 --hardware cuda -o fdk.mha
The result looks good to me. Obviously, when I run
rtkfdk -p . -r ^proj.mha$ -g inverse.xml --spacing 0.5 -d
300 --hardware cuda -o fdk.mha
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?
Hi Simon,
thanks for the explanation. I'll have a go later today or Monday, but I
will definitely let you know what was the result.
Have a nice week end,
Vincent
_______________________________________________
Rtk-users mailing list
[email protected]
https://public.kitware.com/mailman/listinfo/rtk-users
