12 Camera indoor setup

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oschnit
Posts: 10
Joined: Sun Aug 16, 2009 11:50 am

12 Camera indoor setup

Post by oschnit » Sat Sep 26, 2009 3:01 am

Hello,

My colleges and I use 12 Opti-track cameras for position & orientation feedback in an automatic vehicle control laboratory.
The room floor is about 4x6 meters and the ceiling is not much higher than 3 meters. We have placed the cameras as suggested (12 camera truss setup, but drilled to a wall instead of a truss). Our capture volume is not good enough. The corners of the floor are dead zones and the higher up you go the dead zone grows until a height of 1.5 m' where not even the middle of the room is covered.
The captured volume as seen in the tracking tools program is mostly underground. We believe the reason is that the cameras are not high enough. If we try to point the cameras a bit up, they see each other which we understand is bad news.
Would adding more cameras help?

Is it a good idea replacing to large field of view lens and replacing the passive reflectors with 850nm leds on the vehicles?

Ory Schnitzer

bsteagal
Posts: 311
Joined: Tue Jun 28, 2005 5:00 am
Location: Albuquerque, New Mexico

Re: 12 Camera indoor setup

Post by bsteagal » Sun Sep 27, 2009 8:26 pm

Ory:

Having the cameras see each other is not a bad thing, and many times you really cannot avoid it.

If you have already eliminated any other sources of stray markers in your capture volume... (shiny materials, reflective materials, etc) when you use the "block visible markers", it will only be a few pixels that it cuts out of the volume.

You will always lose about half of your space, regardless of how well you set up the cameras. Is the room itself those dimensions? or is that the dimensions you want to capture? If the room is that size, your effective capture volume will only be about 2x3 meters. That is why the recommended capture "space" is roughly 6x6 meters, with a capture "volume" of 3x3 meters..

Having more cameras might help, but you would have to really experiment with the placement. (the suggested placement for cameras on the website is more for motion capture of a person anyway than for your application...) I don't think you would really need to resort to leds, you can also solve that with having a larger passive marker. (when you use leds, you have to disable the IR on the cameras)

Could you describe a little more of what you are capturing? are the vehicles scaled down? (model cars?) If they are.. then perhaps it might be better then to set ALL of them up about waist high, equally around the room.. set vertically (normal orientation) so they have the widest POV horizontally... that way you will cover more of the corners.

With more information of what you are capturing...the better we can help

Sorry for the long rant! I'm happy to help...
Bryan Steagall
Owner
Kidz Korner Studio
OptiTrack Distributor
Mexico, Central and South America
505-615-2410
bryan@kkstudio.us
www.kkstudio.us

oschnit
Posts: 10
Joined: Sun Aug 16, 2009 11:50 am

Re: 12 Camera indoor setup

Post by oschnit » Mon Sep 28, 2009 6:15 am

Thanks! We are tracking a group of 4-5 RC cars and helicopters and controlling them real time (A computer calculates a control signal depending on the tracking info). This means that not only much of the floor should be captured (for the cars) but also as much volume as possible (for the helis). I will try the idea with the all horizontal setup. Tracking tools has an option to split the cameras into groups. What is the benefit in this? Another problem is that the Helis move very fast and when this happens, tracking is not so good, even in the middle of the capture volume. Can the shutter speed of the cameras be change d and will that help? (Maybe for this IR leds would be needed?). Maybe different setting of the rigid body in tracking tools may assist?

Thanks again, Ory Schnitzer

beckdo
NaturalPoint Employee
NaturalPoint Employee
Posts: 519
Joined: Tue Jan 02, 2007 2:02 pm

Re: 12 Camera indoor setup

Post by beckdo » Mon Sep 28, 2009 3:04 pm

Ory, you might want to send me a specific timeline recording highlighting a specific tracking problem along with a camera calibration so that I can setup and reproduce the problem you're experiencing. From there I can likely give you suggestions on how to mitigate the issue via tracking or RB settings.

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