skeleton over time loses calibration

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g0ll4m
Posts: 3
Joined: Tue Feb 15, 2011 11:32 pm

skeleton over time loses calibration

Post by g0ll4m » Tue Feb 15, 2011 11:36 pm

just wondering if this is normal, but after an hour or two of mocapping with the 10 cam setup, the skeleton gets increasingly twitchy over time.

Is this possibly a result of marker sliding on the suit? Under garments worn with the suit cause marker sliding? Or changes in lighting conditions in the capture wherehouse?

Then if i try to recapture the skeleton the cameras pick up 39 and 40 markers when there are only 34 on the suit.

thanks

NaturalPoint - Mike
Posts: 1896
Joined: Tue Feb 01, 2011 8:41 am
Location: Corvallis, OR

Re: skeleton over time loses calibration

Post by NaturalPoint - Mike » Wed Feb 16, 2011 3:09 pm

The twitching skeleton could be the result of markers sliding on your suit. I would look at recreating your skeleton when you start experiencing those issues.

If your excess markers appear to be duplicates of markers on your suits, this could indicate an issue with your calibration. If they appear to be floating static markers, greyscale mode could help you identify the cause of the errant IR light so that you can appropriately mask it.

g0ll4m
Posts: 3
Joined: Tue Feb 15, 2011 11:32 pm

Re: skeleton over time loses calibration

Post by g0ll4m » Wed Feb 16, 2011 4:00 pm

ok thanks good info. Although I do often recreate the skeleton, and sometimes it works but then other times it doesnt seem to help. Regarding the calibration, i almost always get Exceptionall or excellent on the camera quality results.

Is it possible the cameras might be too far away from the capture area, or not oriented in the most efficient way.

Also its unfortunate but we have a wherehouse space with a skylight, as the day goes by lighting conditions change. Could this be another possibility for the loss of calibration over time?

NaturalPoint - Mike
Posts: 1896
Joined: Tue Feb 01, 2011 8:41 am
Location: Corvallis, OR

Re: skeleton over time loses calibration

Post by NaturalPoint - Mike » Wed Feb 16, 2011 4:49 pm

The skylight could potentially be a huge problem. The sun is a massive source of IR light, and even though it might not be coming directly at the cameras, natural light can reflect and cause phantom markers to show up. It would be highly recommended that you mask off any sources of incoming daylight and use either incandescent or flourescent light for your workspace.

The_Nomad
Posts: 57
Joined: Tue Mar 04, 2008 9:55 am

Re: skeleton over time loses calibration

Post by The_Nomad » Mon Feb 21, 2011 6:55 am

I've had this problem too. We've found that a full recalibration helps temporarily - however, sometimes even if we recalibrate and create a new skeleton, I recall having increased inaccuracy problems.

It's not a killer problem, and recalibration helps a lot, but I'd love to know why it happens!

lovegod710
Posts: 1
Joined: Fri Mar 04, 2011 12:51 am

Re: skeleton over time loses calibration

Post by lovegod710 » Fri Mar 04, 2011 12:54 am

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