Good ! Thanx a lot David. ++
Jack
Le 7 mars 09 à 15:40, David Kirkpatrick a écrit :
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: pd-list@iem.at From: jack@rybn.org Subject: Re: [PD] Pd/GEM and camera for tracking Date: Sat, 7 Mar 2009 13:15:16 +0100 To: djk_1200@hotmail.com
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:
- 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.
- 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.
- 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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