CctvCameras

Zoneminder linux based DVR and motion detection system
ZoneMinder

Spectral response and CCD sizes
The larger the CCD sensor the better the spectral response or the better image resolution is achieved. 1/2'' CCD coupled with an Infra-red laser can detect motion at 800m. 1/3'' provides a good trade-off between cost and performance. 1/4inch, 1/3 and 1/2inch are sizes used for nightvision. The lux value must be at least 0.01lux for long distance vision.

Watec cameras are prefered for CCTV
*South African distributor of http://www.wateccameras.com: Scientific Alert 011 476 5718 *0.08lux camera R570 *See AstronomyCameras for further info *Dave Brown R1600,00 *0.01 R1600 code: 902b *0.003 R1900 code: 90282

pulnix
http://www.pulnix.com/Defense/Defense1.htm

Pulnix has UltraViolet sensitive cameras.

Nightvision
Nightvision for CCD are achieved in the 820-880nm(semi-covert) and 940nm(completely covert) pectrum. A cluster of high power www.roithner-laser.com diodes(820nm) will glow like red dragon eyes which are not allowed besides the road since it will look a red robot. For street surveillance 940nm must be used which is completely invisable to the human eye. The diodes are more expensive and the spectral response of the CCD must sensitive in the 940nm region. To prevent headlights from blinding the camera a IR filter lens is attached. Discriminating between a human walking down the street and a car driving past is possible. See www.zoneminder.com wiki for details on this.

www.baxall.com sells a camera with an A/D converter on every pixel of the CCD sensor. The camera is usually used to attenuate sharp light overloading the CCD sensor. http://www.reditron.co.za will be able to provide more info on the Baxall range. www.axis.com ethernet camera's CCD sensor are not suitable for nightvision applications. A high end mini-itx connected to a KMC-4400r or Pico capture card should be used and the mini-itx ethernet port connected to the network. http://ffmpeg.mplayerhq.hu are used by Zoneminder to stream Jpeg images over the network. In this way an Axis ethernet camera functionality is simulated. For a high current(2A, 12v) long range IR camera like the E-558(eaglecctv) use a standard PC power supply. Bridge the Green and Black contacts on the ATX connector to power it up.

CCD sensors
http://www.amazon.com/gp/product/0521648343/qid=1149096194/sr=1-10/ref=sr_1_10/002-9750372-8694448?s=books&v=glance&n=283155

1/4, 1/3, 1/2 inch Ccd's
In the days of vcr's we all used to use wither vhs (240 tvl colour) or svhs (supossidly >400tvl) and cameras were either med res (380 tvl b/w/330 colour) or high res (570 tvl b/w 480 tvl colour). Now as you could only resolve 240 on vhs why use high res cameras? Well you do end up with a slightly sharper image from high res kit even though your only recording the same actual number of pixels, i assume its to do withthe way the camera makes 380 tvl source into a 625 tvl transmission but i dont know. I would say always go for high res where possible (on the cam front)

Note on format sizes 1/4 1/3 and 1/2 inch ccd's all have (or can have) the same number of pixels. As most cctv is made from camcorder chips we tend to follow that industry, thats why the really specilist cctv are so much money (1/2 frame transfers etc). Even though a 1/4" can produce the same number of pixels a 1/2" chip can it needs a lot more light or gain to be able to do this. This is why cheapo cams have leds on them as they use 1/4 pickups and through their own light rather than 1/2 which can use clear starlight. Id go with a 1/3 as its a good balance between cost and low light performance. But if you have the light it matters little. Plus the smaller factors need cheaper lenses so you can save there.