[Elphel-support] Camera Calibration

[Sinaya Dayan]

Hi Andrey,
Here is one of the image sets we took along with the target measurements and its calibration report.
The analyst approved that the images are good for calibration. We have set the focus to infinity (@48.5 mm) the entire time and the target size was 3 x 2 meters. We have not changed anything in between images part from the camera's position.
"Hardware problems" according to the analyst could be a small internal movement that could jeopardize the image and result in an in consistent error.
Please have a look and let me know what you think.
Thanks,
Sinaya
From: elphel at gmail.com [mailto:elphel at gmail.com] On Behalf Of Andrey Filippov
Sent: Friday, July 06, 2012 3:21 PM
To: Sinaya Dayan; support-list at support.elphel.com
Subject: Re: [Elphel-support] Camera Calibration

But let me have a look at the images anyway - maybe I'll notice some simple problem.
"hardware problems" - what can that be? If camera is not working - you'll notice that easily. What else can jeopardize calibration? I can think of:
1 - changing camera settings acquisition parameters (especially WOI) between shots
2 - changing lens settings (focus)
Other than that (if the images look OK - normal brightness, contrast) - I can not think of anything.

One more thing after (I read their instruction) - some problem withe the pattern you used, it may not be an easy task to do that correctly. We use different pattern ( http://blog.elphel.com/2011/10/subpixel-registration-and-distrortion-measurement/ )  and we calibrate the pattern itself too using many more measurements from different locations, so for us minor errors in the target (i.e. non-flatness) are not critical, but they probably are important in the calibration they use.

Andrey

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