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- June 2005 -
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SURVEILLANCE: THE NEXT STEP UP
FROM USB WEBCAMS
If you like what computer-based surveillance gives you but have been hindered by USB cable length or image quality, know your options and take a look at high-quality analog.
As you develop your computer-based surveillance system, are you growing frustrated with USB webcams? They certainly are versatile, cheap tools, but as your needs become sophisticated, you begin to run into some limitations inherent in these devices. Among them: the short maximum distance possible between a webcam and the PC controlling it. Also, the so-so video quality, which gets downright awful in low-light conditions. If you find yourself starting to push up against these limits, then it's helpful to know what's available to someone looking for the next step up from USB webcams.
There are two main choices if you are looking for a way around short cable lengths between camera and computer: network cameras and analog cameras. Network cameras need no computer to run, just a LAN port, so you can scatter them throughout a large building if there's LAN wiring in place. You access video by logging in over the LAN from another computer. They are a good choice for some people, but very expensive if you don't have a LAN set up at the site with Ethernet cabling running through the building. Video quality is also, typically, no better than that of USB webcams. (Wireless network cameras also exist and let you do away with the need for cabling, but, in addition to poor video quality, the video frame rate is very slow and becomes even slower whenever other devices communicate over the same network.)
And so we arrive at an old/new choice, analog cameras. These output their video on a coax cable, which is what you use to connect old-fashioned cable TV to your TV set. You can run this cable hundreds of feet to the monitoring computer with no problem. The cabling itself is very cheap and you might even already have it installed in the building if CCTV was ever used for surveillance.
Contrast a 500-foot analog cable with the 6-foot standard USB cable and you see why someone mounting cameras at locations throughout a building should consider analog cameras.
Analog cameras offer varying levels of video quality. There are now very good quality high-end analog cameras on the market. Compared to USB webcams, their video image is excellent, even in low light. They also offer optical zoom and auto-focus. In the event of a robbery, a detailed, recognizable image you can give to police is what you want from your surveillance system and unfortunately USB webcam images are hit-and-miss on that count.
Finding a quality analog camera, with good low-light performance, auto-focus, and optical zoom that can be controlled by a computer is difficult. A good place to start is a product called ClearPTZ, available at www.trackercam.com. It's a complete package with camera, pan/tilt base, and software for your computer.
With the advantages of these analog cameras come difficulties: increased cost compared to USB webcams and increased complexity in set-up. You can't just plug the video cable from an analog camera into your computer as you do with a USB webcam-- you need to buy and install an analog video capture card and plug the camera video into that.
Unfamiliar with analog video capture cards? They're the same cards people use to watch TV on their computers. They take an analog video input--whether from cable TV, a VCR, or a surveillance camera--and turn it into digital video images computers can display and use. You can get these cards quite cheaply now (the ClearPTZ package mentioned above is offered with an optional capture card for $50 over the regular price).
So, if you like what computer-based surveillance gives you but have been hindered by USB cable length or image quality, know your options and take a look at high-quality analog.