<div dir="ltr"><div><div>Ok, sorry, I erroneously mixed the size of the reconstructed volume and the size of the projections. Then your calculation seems correct and I don't know where does your geometry problem come from. For sure, you don't have to shift the projections, --proj_iso_x does the same thing directly.<br></div>Regards,<br></div>Simon<br></div><div class="gmail_extra"><br><div class="gmail_quote">On Thu, Mar 17, 2016 at 4:23 AM, Vasiliy Nabokov <span dir="ltr"><<a href="mailto:nabokajeleboka@gmail.com" target="_blank">nabokajeleboka@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr">Dear Simon, as i understand --neworigin is origin for projections. my projection's width 2452 and spacing 0.0148, so 2451/-2*0.0148=-18.137</div><div class="HOEnZb"><div class="h5"><div class="gmail_extra"><br><div class="gmail_quote">On Wed, Mar 16, 2016 at 6:45 PM, Simon Rit <span dir="ltr"><<a href="mailto:simon.rit@creatis.insa-lyon.fr" target="_blank">simon.rit@creatis.insa-lyon.fr</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div dir="ltr"><div><div>Hi,<br></div>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.<br></div><div>I hope this helps,<br></div>Simon<br></div><div class="gmail_extra"><br><div class="gmail_quote"><div><div>On Wed, Mar 16, 2016 at 1:11 PM, Vasiliy Nabokov <span dir="ltr"><<a href="mailto:nabokajeleboka@gmail.com" target="_blank">nabokajeleboka@gmail.com</a>></span> wrote:<br></div></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div><div><div dir="ltr">Hi dear RTK users. Sorry, its offtop post... i just wanna tell you about my problems if anyone can help me..<br>I develop scanner. Reconstruction of parallelepiped or cube (<a href="http://i.imgur.com/9YHyfWH.jpg" target="_blank">http://i.imgur.com/9YHyfWH.jpg</a>) caused to phantom artifact (<a href="http://i.imgur.com/yyI184j.png" target="_blank">http://i.imgur.com/yyI184j.png</a>). 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 <br><a href="http://www1.jinr.ru/Pepan_letters/panl_2015_5/10_gongad.pdf" target="_blank">http://www1.jinr.ru/Pepan_letters/panl_2015_5/10_gongad.pdf</a>, got sourceX = -215 mkm, sourceY = 650 mkm, detectorX = 50mkm. i specify this information but without success.<br><br>I also wrote a little program in this way<br> for (float sourceXOffset_ = sourceXFrom; sourceXOffset_ < sourceXTo; sourceXOffset_ += searchStep)<br> for (float sourceYOffset_ = sourceYFrom; sourceYOffset_ < sourceYTo; sourceYOffset_ += searchStep)<br> for (float projXOffset = projXFrom; projXOffset < projXTo; projXOffset += searchStep)<br> {<br> 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);<br><br> int r = system(cmd);<br><br> 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");<br> r = system(cmd);<br>...<br><br>to search scanner alignment but also without success.<br><br>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! (<a href="http://i.imgur.com/OOsPsfL.png" target="_blank">http://i.imgur.com/OOsPsfL.png</a>) 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 <a href="http://i.imgur.com/FGxCJUo.png" target="_blank">http://i.imgur.com/FGxCJUo.png</a> to <a href="http://i.imgur.com/brbp5sd.png" target="_blank">http://i.imgur.com/brbp5sd.png</a>), 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 =))<br><br><br>What do you think about it ? If its geometry issue, why real or virtual offset of detector cleans up the phantom artifact?<br><br></div>
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