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 <v...@xris.eu> 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 <v...@xris.eu> 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? >> > >
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