[PD] Pd/GEM and camera for tracking

[Martin Schied]

hey all,

Jaime Oliver schrieb:
> mmh, I don't really know about lengths. I think there is a limit to 
> how long your firewire cable should be. I usually work with analog 
> cameras in linux where cables can be long ad I capture with a pci card.
>
> I think a cheap option that I've seen working well with macs is the 
> unibrain fire-i:
> http://www.unibrain.com/Products/VisionImg/Fire_i_DC.htm
>
> you can buy lenses and chain them, not more than 30fps though,
>
> J
lengths between firewire 400 devices is usually 4.5m, but you can daisy 
chain them up to 16 times giving you 72 metres. it's not very 
recommendable to make long chains, as every plug may be a "weak point" 
in your chain. firewire 800 can have longer cables, but i don't know...

Jack schrieb:
> Thanx for the reply. The models are too big for me. I need a smaller 
> camera (something like a cube) because the installation must be 
> discreet. Have you something else to suggest ?
> Chris : what do you think about Sony driver ? I can't use a PCI card 
> because i will work with a macmini.
> ++

as manufacturer of small firewire cameras there's also "point grey". I 
don't know exactly about cost, and didn't try them on my own but they 
often were recommended by people doing tracking, also being said they 
were affordable, especially the "firefly mv" which delivers 
60fps at 640x480 and even higher frame rates at lower resolutions.

that's what they say about macintosh (seems to work):
http://www.ptgrey.com/support/kb/index.asp?a=4&q=173

i also made tests with usb webcams (only on linux and windows), some 
with usable results but most of them are crap. to be usable they should 
support "real" usb2.0 for high frame rates at full sensor resolution 
(usually 640x480), without compression and have ccd sensors for better 
quality and light sensitivity. (finding out usb version and other 
technical stuff can be real pain from manufacruerer sites, usually 
you'll have to try them).
image quality was always worse than cheap video cameras - but as an 
advantage they were not interlaced like usual consumer video cameras. 
cable lengths can be extended by usb hubs or "repeater" cables several 
times, but that's also the "many-connectors - many errors" thing

@Jack: what exactly will your tracking method be based on? natural 
features? colors? markers? with some luck a cheap usb webcam  could be 
good enough and also really small. (yeah, i'm a fan of using cheap 
consumer producs and having trouble with them - be warned)

cheers,
Martin