Camera placement 18 cam flex 3 system

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kettlefish
Posts: 2
Joined: Wed Jun 17, 2015 9:58 am

Camera placement 18 cam flex 3 system

Post by kettlefish »

Hello there,

I work for an educational institute and our programme has recently inherited an 18 camera system from an old research project, and I have a couple of quick questions. The system was originally in a small room, mounted on stands. Consequently the capture volume was quite small. Although I'm familiar with the system (using it), we are moving it to a new larger location and would appreciate some advice on configuration.

The cameras are all flex 3
The room is 7m x 12m x 3m
Intended use is full body capture for animation of single characters (student use)
Cameras can be positioned anywhere (will be attached to walls)

My questions:

1. Do we need lower cameras? I've seen several suggested configurations some with and some without lower cameras. Would 18 high cameras in portrait work well, it seems to me that it would minimise occlusion problems, but I'm not that experienced with this.

2. Would it be a good idea to limit the size of the space to make the sides even, i.e. 7m x 7m.

3. Body capture is the main focus, but it wouldn't hurt to have some facial capture as well, would limiting the body capture system to 12 cameras and using 6 for facial capture be advisable? I'm a little worried about occlusion problems cropping up with only 12 cameras for the main rig.

Thanks in advance for any advice you can provide

Kettle.
steven.andrews
NaturalPoint Employee
NaturalPoint Employee
Posts: 737
Joined: Mon Jan 19, 2015 11:52 am

Re: Camera placement 18 cam flex 3 system

Post by steven.andrews »

Hello kettlefish,

Thank you for reaching out to us regarding your questions. You seem to have some understanding of the setup, and I would be happy to address your questions.

1. Do we need lower cameras? I've seen several suggested configurations some with and some without lower cameras. Would 18 high cameras in portrait work well, it seems to me that it would minimise occlusion problems, but I'm not that experienced with this.

Lower cameras are not a requirement, but are sometimes used if size constraints prevent the cameras from being mounted far enough away from the volume to see the full body. Lower cameras are also, sometimes, considered useful if actors will be performing moves in which they bend over often, as lower cameras can help to track markers that the high mounted cameras may no longer see.
In general, mounting the cameras up top around the entire perimeter works just fine.


2. Would it be a good idea to limit the size of the space to make the sides even, i.e. 7m x 7m.

I do like this idea. It is good to limit and to know the size of the space you are aiming for. In general, the rule of thumb when mounting cameras and covering a space is to be sure there is a 50% overlap between cameras that are beside each other. This is to insure that at least two cameras will be able to see a marker at any given point, so the marker can be tracked.


3. Body capture is the main focus, but it wouldn't hurt to have some facial capture as well, would limiting the body capture system to 12 cameras and using 6 for facial capture be advisable? I'm a little worried about occlusion problems cropping up with only 12 cameras for the main rig.

I do not recommend facial capture with the Flex 3 in your space.
Is the thought, here, that you would have a separate system of 6 cameras that is used for seated facial captures?


Cheers,
Steven
--
Steven Andrews
OptiTrack | Customer Support Engineer
kettlefish
Posts: 2
Joined: Wed Jun 17, 2015 9:58 am

Re: Camera placement 18 cam flex 3 system

Post by kettlefish »

Hi Steven

Thank you very much for your response, it's a great help.

As to my last question, regarding facial capture. Yes, I was thinking of six camera's set aside for seated facial capture. I'm just worried that 12 cameras in the main rig would increase the chance of occlusion and reduce the usable volume for full body capture.

Thanks for your help

Kettle
steven.andrews
NaturalPoint Employee
NaturalPoint Employee
Posts: 737
Joined: Mon Jan 19, 2015 11:52 am

Re: Camera placement 18 cam flex 3 system

Post by steven.andrews »

Hi Kettle,

My pleasure; I'm happy to help.

12 cameras is still a good number and would normally be suitable for capturing two people in an area of about 10 feet by 10 feet. If you need a bigger volume, you might want to consider keeping those cameras as part of the main rig to be sure you are adhering to the guideline of about 50% overlap in the camera views.

Cheers,
Steven
--
Steven Andrews
OptiTrack | Customer Support Engineer
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