Hi Jack,
 
Yep, your chain is right. A minor difference is that I use two BNC baluns (one 
with a BNC to composite adaptor attached), but it should make very little 
difference. I also used a UTP cat 6 cable instead of cat 5, but I used cat 5 
baluns.
 
I've used this chain in multiple theatrical projects without noise issues, even 
with moving lights messing up the ambient light levels. Obviously you would 
have a dodgy signal if you ran the UTP cat 5 or 6 alongside a 3 phase lead or 
something, but apart from that you should be fine. I had the cat 6 lead running 
through a lighting grid full of 240V and it didn't degrade. It actually seemed 
cleaner than doing everything with coaxial cable.
 
David Kirkpatrick



CC: [email protected]
From: [email protected]
Subject: Re: [PD] Pd/GEM and camera for tracking
Date: Sat, 7 Mar 2009 13:15:16 +0100
To: [email protected]

Hello David,


Thanx for all this informations using an analogue camera.
It's good to know there is FireWire extensions, but it is very expensive (245 
pound sterling !).


If i understand, the system is like this :
Analogue camera with BNC -> BNC baluns with power -> cat 5 cable -> composite 
baluns with power -> composite to FireWire400 converter -> FireWire400 to 
FireWire800 cable -> MacMini -> Pd/GEM ?


I know that analogues cameras are good solutions, but with all this stuff, 
there is no risk of noise ? ;) (tell me if i'm wrong).
++`


Jack




Le 7 mars 09 à 06:18, David Kirkpatrick a écrit :



Hi Jack,
 
I've done a fair bit of this sort of thing before. The most useful setup i've 
found is:
 
1) Analogue monochrome CCTV camera. (Preferably with around 700 horizontal 
lines or so, very low lux, and self syncing)
I use these. 
http://www.allthings.com.au/Catalogue/CCS/monochrome%20low%20light%20cctv%20dsp%20video%20camera.html
You can then buy a C or CS lens that is the right angle for your situation. For 
roof mounted stuff I use an ultra-wide angle varifocal set to just before it 
noticably fisheyes.
 
2) Cat 5 balun connected to CCTV camera's analogue video output and power 
input. This allows signal to be sent, and power to be recieved via a single 
cheap UTP Cat 5 lead (i've gone 30 metres with no noticable image quality loss, 
supposedly you can go much further). Removes the need to run a mains power lead 
or coax lead to the camera so setup is quick and easy, and reduces time spent 
dangling from ladders. You can get sets of cat 5 baluns really cheap on ebay.
 
3) Second cat 5 balun, on the other end of the cat 5 lead, placed next to 
computer. Connect to a suitable power supply for your video camera, and connect 
signal to a near zero latency industrial firewire capture device such as a 
DFG/1394-1e. 
http://www.theimagingsource.com/en_US/products/converters/dfg13941e/ This 
allows you to hook up to a to a desktop or laptop, including a mac mini.
 
Then you're done. Just set Pd to listen to the DFG/1394-1e. Image will be clean 
and roughly equivalent to 720x576 res.
 
This setup can also be modified to work with near infra-red light instead of 
visible light if you want to avoid detecting lighting changes as movement. Just 
tape three squares of primary red and congo blue gel in front of the camera 
lens. Set up a few PAR56s to flood the space with light. Add the same gel to 
the 56's as you did to the camera and it will block almost all visible light. 
People will glow bright white when viewed through the camera, but most other 
stuff in the space will be close to invisible.
 
 
Alternately, if you want to use a firewire board camera, you can get something 
like a Lindy CAT5 FireWire Extender. They aren't cheap but they extend the 
maximum length of a firewire run from around 5m to 70m without quality loss.
 
 
Regards,

David Kirkpatrick





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