Surveillance System Features
Homes and small businesses have just as much need for physical security as their warehouse and data center counterparts. But smaller organizations may not have the on-staff expertise or budget for a high-end security deployment. If this sounds like your situation, don’t worry. There are plenty of affordable ways to set up surveillance in your setting, and it doesn’t take a computer scientist to handle the networking. The first thing to remember is that you’ll likely have a much easier deployment, as well as more functionality for less money, if you opt for a surveillance system based on IP (Internet Protocol) networking rather than older, analog CCTV (closed circuit television) technology. CCTV still dominates in many stores, and professional security installers still opt for CCTV as a first choice because it’s where they have many years of experience. But you want digital, and we’re going to show why by examining a few security options. Computers Repair Las Vegas NV!
Elements Of A Solid Surveillance Kit
There are three basic things you want a security package to do:
- Provide remote visibility into a given area.
- Detect and record intruders.
- Alert you through multiple means when intrusion is detected.
If you’ve ever compared a Blu-ray movie to its VHS equivalent, you know what a difference higher resolution can make. The more resolution (higher pixel count) you have, the more detail you get in a given field of view. If all you care about is seeing if an intruder is in an area, even 320 x 240 resolution will be sufficient. But if you want to make out the intruder’s facial features, you’re going to need more pixels.
The quality of the lens can have a significant impact on the surveillance image you see. Unfortunately, quality is subjective, and there are no mainstream ways of grading lens quality in cameras. Still, generally speaking, a $300 camera will provide better optical quality (and thus better image clarity) than a $100 camera, all other factors being equal. The quality of the sensor recording images from those optics can also play a role in defining clarity.
A camera with an integrated microphone will let you hear what’s being said or done in the camera’s environment. Some cameras offer a port for plugging in an external microphone. This usually adds overall cost but can yield superior audio clarity. Also note that some cameras include speakers, enabling two-way conversations between you and the people being observed and/ or the playback of a recording in case an intrusion alarm is triggered.
Most low-end cameras are fixed-position. Wherever the lens points, that’s what you see. However, many mid-range cameras incorporate motorized panning (side to side) and tilting (up and down) that you can control remotely. When trying to cover a broad area with only one or two cameras, “PT” capability is extremely useful. Higher-end cameras may offer optical zooming, just like on handheld still and video cameras. This feature is most useful in environments that are being actively monitored throughout the day. Note that some cameras may try to emulate PTZ (pan-tilt-zoom) functionality digitally. This involves isolating a central part of an image, then scooting the borders of that cropped area around within the original image. You can’t see any additional detail with digital PTZ.
When triggered by an alert, some security cameras can store video straight into an inserted flash memory card (usually Secure Digital type). This enables video capture even if Internet connectivity is lost. Preferably, though, you want to store video away from the camera first, then on the camera as a backup measure. Some cameras can stream recordings straight into an FTP (File Transfer Protocol) site, but most will relay streams back to a PC running some sort of surveillance client application.
Cameras with excellent sensors may be able to capture clear images in very low light conditions, but in our experience, these are nearly useless for surveillance because shutter speeds become so slow. If the camera is only capturing two frames per second in near-dark conditions, any recorded movement is likely to look like a smear. The better approach is to use a camera with infrared lamps. Infrared is invisible to the eye, but most camera sensors treat it like regular light, so you get greenish/gray night vision footage. Even if your camera doesn’t integrate IR lamps, you can always buy a separate IR lamp and point it within the camera’s field of view.
Smart Computing | October 2011 p.71
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