Getting the most from an analog system

Technological improvements are making "old" surveillance systems new again


You may also find that today's cameras feature a number of "problem-solver" features that would have been difficult or impossible to find five years ago. For example, take Digital Image Stabilization, a feature which removes the shake from an outdoor camera that gets buffeted in the wind. A number of cameras now have this feature as a standard menu option, and when needed, it dramatically improves the image quality by processing the video and locking the objects that are not supposed to move in one place.

Best of all, the cost of a good high-end analog camera has dropped close to 20 percent over the last five years, while gaining a dramatic level of functionality. If you have a limited budget, camera upgrades are a likely and simple place to start.

Upgrade the Monitors

So you replaced some of your cameras and you do not see much of a difference? Do not forget about the other weak link in the chain, your monitor. Yes monitors have improved as well. Beyond that, yours is likely not producing the same picture as it was the day you bought it. First, CRT monitors grow dimmer every day they are used, and 24-hour operation adds up quickly. LCD monitors up until very recently were illuminated with small florescent tubes (ccfl) which also dim with use. The loss of brightness is gradual and therefore hard to notice, but one look at a new monitor next to an old one tells the story. A dim monitor has a dramatic effect on image quality.

New monitors have also improved in resolution. A standard LCD monitor today has a native screen resolution of 1280x1024 pixels, which is a 67-percent increase over the LCDs of a few years ago, and a 3.5x increase over the CRTs we used for CCTV. While this greatly exceeds the capabilities of an analog camera, modern DVRs can use all of this new resolution to display multiple images on one screen. The quality of each individual video on a quad image will improve dramatically.

Also, do not forget that older monitors were generally connected to the DVR with a single analog "composite video" connection. When compared to the more modern VGA or even HDMI connections found on today's monitors and DVRs, the old connections produce a significantly poorer image - lower resolution and less sharpness.

Once again, the price of a good monitor has fallen dramatically, and most systems have only a few. This is another piece of your system where an inexpensive upgrade can make a major difference.

Upgrade the Recorders

There is one more link in the chain, and that is your DVRs. Here too, there have been changes that could enhance the performance of an analog system.

Most DVRs sold in the last few years record at CIF resolution (352x240 pixels) and typically at a frame rate of around 7 frames-per-second per camera for a 16-channel box. Since CIF resolution is about one-quarter of the resolution of a good analog camera, there is a lot of room for improvement. There are DVRs available today that will record full analog resolution (D1: 704x480 pixels) and do so at a full motion frame rate of 30 frames-per-second, if you need that speed.

The case for full resolution is easy to understand. Resolution and the width of the scene you wish to monitor go hand-in-hand. If you want to view a wide scene, for example a parking lot, and still view details, you need a lot of pixels or lines of resolution. How much? Well, a rule of thumb is 20 per foot is the minimum for general surveillance, while a clear view of faces requires 40-80 per foot. So, at CIF resolution, the number of lines/pixels of resolution is severely limited and that limits the width of the scene you can view and still see the details. In fact, with CIF, that width is a maximum of 17 feet and even then, you will not be able to read a license plate. If you want a clear view of faces with CIF resolution, you will have to zoom in to a scene width of no more than approximately 8-9 feet!

So, bottom line, an upgrade to your DVRs will enable you to either get a significant improvement in the quality of your existing camera views or the ability to zoom out for increased situational awareness. Either way, the move to D1 resolution is well worth the upgrade.

Of course higher resolution means more storage, but the good news here is that new DVRs use the latest SATA hard disk drives. These drives are not only available in very large sizes (as much as 2 terabytes of video) but are also available for some amazingly low price points. In fact, hard drive costs have dropped from $1.40 per GB five years ago to 7› per GB today. The cost of storage is less and less of an issue. Many vendors have DVRs today that support 6TB of storage. That will support 45 days of D1 recording on 16 channels at 7.5 fps at a cost far less than you paid for your five-year-old CIF DVR.

An Achievable Plan