[Rtk-users] need help with geometry

1 1 infrombox at yandex.ru
Sat Mar 21 16:41:41 CET 2015


Hello RTK users. I am newbie in RTK but its interesting to me because of open source code! I wonder if i could get it worked
But for this moment i can't reconstruct my test projections.
I use SkyScan tomograph (cone beam) and after acquisition process i have set of tifs and .log file which contains meta info.

In my test i rotate bug on a table - gantry rotation, one step: 0.45 degrees, total rotation: 199.35 degrees (444 steps) and all other info presents in meta file.

In the following sequence i use every 3rd projection
rtksimulatedgeometry -o geometry.xml --n 148 --arc=198.45 --sid=214.119 --sdd=91.770
rtksubselect --geometry=geometry.xml --out_geometry=sub_geometry.xml --out_proj=sub_proj.mhd -p tifs -r .tif$
rtkfdk -p . -r sub_proj.mhd -o fdk.mha -g geometry_sub.xml --verbose --dimension 1000,500,1000 --spacing 0.009,1,0.009

but fdk.mha contains blank black cube. i play with geometry params all day long, but have nothing results =) especially with spacing... as i understand in auto-generated mhd file the spacing values based on dpi info in tif, but what is 1 for z ? should i change it ?
so now values:
in auto-generated proj_sub.mhd: 0.00901029 0.00902951 1
on rtkfdk call which i set: --spacing 0.00901029,1,0.00902951
i want to set the same spacing, because i want the same spacing in volume, but i am not sure that i do it in a right way.
i tried different variations of spacing, but nothing changes in result... could you explain me with spacing there a bit

but problem may be not in/not only in spacing,

these tomography scans reconstructs in another software, so i have no doubt that RTK can do it, i just have set right geometry.

pair mhd/raw generated by rtksubselect: https://drive.google.com/file/d/0B9EY8AokXE8zSHZqaUJ5UmtHa1E/view?usp=sharing (163 MB)
meta file: https://drive.google.com/file/d/0B9EY8AokXE8zaWw0aFdRWUQ0d2c/view?usp=sharing
i can share original tifs if needed.

offtop: seems files 00.mhd, 00.raw at http://wiki.openrtk.org/index.php/RTK/Scripts/ForwardProjection are not accessible.

thanks



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