[Rtk-users] Geometric calibration

[Sepp de Raedt]

Hi Simon,

Thanks for the script. I was wondering if you could also share the csv or a dummy file? I'm unsure of what the second column contains. An offset distance to the rotation axis? Or the height?

Which distance was known in your example? From the code it looks like the distance to the rotation axis?

Sepp

On 22 Nov 2016, at 08.01, Simon Rit <simon.rit at creatis.insa-lyon.fr<mailto:simon.rit at creatis.insa-lyon.fr>> wrote:

Hi Sepp,
I did do a calibration script on a micro CT platform. The idea was that I had a bb taken from 4 different view points at 4 different heights with a known distance. Their projected position was segmented beforehand on the projections and I tried to match the projections by optimizing the calibration (which we see in before.pdf and after.pdf). I don't think it's a good script, e.g., because I tried to find 8 parameters when 7 are sufficient for my system (see, e.g., this paper<http://iopscience.iop.org/article/10.1088/0031-9155/45/11/327/meta;jsessionid=8DD0F1160098FBC65BB161A0257FBA75.c3.iopscience.cld.iop.org#>). But this gives you a starting point to develop your own script which will hopefully be better. Please share if you do something from it!
Thanks,
Simon

On Sat, Nov 19, 2016 at 8:51 PM, Sepp de Raedt <sdr at nrtxray.com<mailto:sdr at nrtxray.com>> wrote:
Hi RTK users,

I'm interested in reconstructing images acquired by a fluoroscopy system rotating around a knee phantom. Unfortunately, I've been unsuccessful so far. I recognize some of the phantom in the reconstructed image, but it contains double contours and the shape is deformed.

I think the issue might be incorrect geometry specification. I have images also including a phantom containing markers for which we know the coordinates, which should allow us to calibrate the system. On the wiki on image quality, I saw that some users had developed scripts to do the calibration? Would someone be willing to share it?

Kind regards,
Sepp

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<after.pdf>
<before.pdf>
<calib.py>

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