Hi, I think it's a geometry problem. I don't have a solution for you but just a remark: how did you come up with the neworigin parameter? Changing this has a similar effect as changing the --proj_iso_x or "offseting" the projections. And it seems that the value you put (-18.137) makes no sense to me wrt the total width (800*0.0296=23.68). Typically, I center the projection which in your case would require as a new origin 799/-2*0.0296. I hope this helps, Simon
On Wed, Mar 16, 2016 at 1:11 PM, Vasiliy Nabokov <[email protected]> wrote: > Hi dear RTK users. Sorry, its offtop post... i just wanna tell you about > my problems if anyone can help me.. > I develop scanner. Reconstruction of parallelepiped or cube ( > http://i.imgur.com/9YHyfWH.jpg) caused to phantom artifact ( > http://i.imgur.com/yyI184j.png). Don't look at noise, its test scan, > without averaging and big rotation step. Yea, it seems that its mainly > misalignments problems, so i calibrated sourceX, sourceY, detectorX, > detectorY by the following method > http://www1.jinr.ru/Pepan_letters/panl_2015_5/10_gongad.pdf, got sourceX > = -215 mkm, sourceY = 650 mkm, detectorX = 50mkm. i specify this > information but without success. > > I also wrote a little program in this way > for (float sourceXOffset_ = sourceXFrom; sourceXOffset_ < sourceXTo; > sourceXOffset_ += searchStep) > for (float sourceYOffset_ = sourceYFrom; sourceYOffset_ < sourceYTo; > sourceYOffset_ += searchStep) > for (float projXOffset = projXFrom; projXOffset < projXTo; projXOffset > += searchStep) > { > sprintf(cmd, "./rtksimulatedgeometry -o geometry.xml --n 90 > --arc=360 --sdd=232.241 --sid=170 --source_x=%.6f --source_y=%.6f > --proj_iso_x=%.6f", sourceXOffset_, sourceYOffset_, projXOffset); > > int r = system(cmd); > > sprintf(cmd, "./rtkfdk --hardware=cuda -p /home/fee/Public/ -r > [0-9]+.tif$ -o dump/out.mha -g geometry.xml --verbose --dimension 800,1,800 > --spacing 0.0296 --newspacing 0.0148 --neworigin -18.137,-12.128,0 > --subsetsize=1 -l --origin -11.8252,-3.55,-11.8252"); > r = system(cmd); > ... > > to search scanner alignment but also without success. > > I noticed interesting thing: when i specially offset detector horizontally > to the right by 4.5mm from the center, and specify it by --proj_iso_x=4.5 > when generating geometry file, phantom disappears! ( > http://i.imgur.com/OOsPsfL.png) I even take scans when the detector on > the center, reconstruct it, and here is phantom artifact, then i manually > offset picture to the left on the tifs (from > http://i.imgur.com/FGxCJUo.png to http://i.imgur.com/brbp5sd.png), and it > reconstructs without phantom with --proj_iso_x=4.5! So, for this moment i > work in this way, take scans when detector on the center, manually offset > picture to the left and specify it by proj_iso_x to avoid phantom artifact, > but its HUGE WORKAROUND =)) > > > What do you think about it ? If its geometry issue, why real or virtual > offset of detector cleans up the phantom artifact? > > > _______________________________________________ > Rtk-users mailing list > [email protected] > http://public.kitware.com/mailman/listinfo/rtk-users > >
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