More and more people are moving to digital-based CCTV Systems over the conventional analog VCR-based systems. This is according to Nathan Bearman of Eagle Technology. "This trend has really taken off in SA over the past few months. Many installers are no longer quoting for analog-based systems and are offering digital technology for all applications, large or small. Digital systems now range in price from R6000-R13 000 for lower-end board products, R40 000-R80 000 for mid range complete systems and R150 000 to millions of rands for high-level systems."
Bearman explains that the benefit of using a digital system is that it allows the user to replace his switching unit, monitor and time-lapse recorder with one centralised system, which he can access and control from several locations. Because the system is automated, one does not have to swop or replace any videocassette tapes, allowing minimum intervention from the system controller. These systems can record video images on the HDD depending on capacity for several weeks. A digital system allows the user to instantly retrieve relevant data. There is no longer a need for screening through hours of videotape to find a single frame of video. Data is stored in a database and can be searched by camera, time, date, alarm-activation or motion. This saves the user valuable time in identifying the target.
Sharp, crisp images are stored which can be replayed over and over again without image deterioration. Yet another advantage of digital systems is their flexibility of recording modes. Recording can be done by schedule (ie time or date), alarm activation or via smart motion detection.
A single PAL video frame uncompressed is about 1,2 MB in size. This would obviously take up large amounts of space, so digital video recording systems feature compression technology which compresses the file down to anywhere from 128 KB to 2 KB. Examples of these technologies include MPEG, JPEG & Wavelett.
Advantages of digital CCTV
* Faster retrieval times - Using digital CCTV, users can immediately retrieve video - even for remote viewing. Users can rapidly search events by time, date, location and camera.
* Less storage space required - Users may set the system to record when motion or other predefined events are detected - so there is no wasted 'dead taping'. Video is then compressed and stored to a PC's hard drive.
* Archiving - Important information can be archived to FDD, HDD, CD-R, DVD for later retrieval, months or years down the line.
* High-quality images - Digital video can be easily enhanced and copied over and over without losing its original quality.
* Transmit and retrieve stored data - Across town or across the world, video images can be remotely viewed, easily saved, retrieved, displayed, copied, printed, faxed and e-mailed.
A recent study determined that in systems using analog technology, only 1% of recorded data was usable. With digital systems, a whopping 50% of recorded data was used in the apprehension process due to better indexing and retrieval.
According to Bearman, there are hundreds of different types of digital systems on the market at the moment and it is important that one buys the correct product. Features to look for in your digital system are stability (reliability and minimum downtime), ease of use (friendly user-interface), good picture quality and encryption watermarking for video integrity. Another very important specification to look at is the recording or capture speed of the system. Many suppliers will give you a specification without informing you of the condition under which it was measured. Recording speeds can vary according to the amount of motion in the picture, amount of cameras connected as well as resolution of the image.
"Eagle Technology is well positioned to offer you advice on a complete range of digital CCTV products ranging from lower cost board products up to multichannel realtime recording systems," concludes Bearman.
For more details contact Nathan Bearman, Eagle Technology, tel: (021) 423 4943, fax: (021) 424 4637, e-mail: firstname.lastname@example.org
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