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RSS >  2 instances of FreeTrack?, or multi-camera support?
HarvesteR #1 30/04/2010 - 22h14

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Registered on : 11/04/2008

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Hi,

I was wondering... I have a project which calls for using 2 cameras and free track to detect the 3D position of a single LED...

I wasn't able to get more than one instance of FreeTrack running (got an error message saying freeTrack was already running), so I was wondering if this is at all possible... or if not, if it is at all possible to get free track to pick up input from more than one camera...

I know that FT can detect 3D position with a 3-LED array, built to spec... but I wanted to see if there were any other options, since having the 3-LED array mounted on your head may look too nerdy for the non-initiated ;)

I have managed to write up some code to calculate the 3D position based on the stereoscopic input from both cameras (something similar, albeit far simpler, than what project Natal is doing)... so with both cameras running FT, I could have a very good tracking base for my application (which has been the problem up until now.... our video tracking program was crappy for this)

Cheers
petroleus #2 01/05/2010 - 20h38

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Registered on : 12/04/2010

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the problem with a single led is not so much that freetrack can't deduce information from it, but rather that you can't have multiple degrees of freedom. I believe freetrack is preset to interpret single led displacement as rotations, but it would not be difficult to change that into translations.

If you have two camera's you'll be able to accurately deduce where the led is in 3d space, but you will still not be able to deduce what type of movement, translation or rotation, got it to that position, hence you will not be able to have all 6 degrees supported.

Furthermore, which I also find strange, Freetrack doesn't care at all where your head is in space, all it does is compare one image with another, regardless of how it was obtained. As illustration: I have my cam looking through a mirror, and reversed the output in FT, which works fine.

EDIT: by the way, this isn't tooo nerdy is it?
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Edited by petroleus on 01/05/2010 at 20h53.

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