By Tom Condon, RPA, FMA
Published in the July 2009 issue of
Today’s Facility Manager
acility management (FM) is nothing if not fluid; it changes constantly. Just when we think we have it figured out, some new law, practice, or technology comes along and changes it. That’s also what’s happening in video surveillance with high definition digital video. It offers some big advantages over traditional digital video and could be the “magic bullet” technology that transforms the way we think about video surveillance.
First, what is high definition video? Every digital image is comprised of many tiny dots called pixels. More pixels mean more detail. This is the difference between traditional and high definition TV; the picture is clearer and sharper due to more pixels. The same applies to surveillance cameras.
The term megapixel describes a camera that displays more than one million pixels per image. A conventional CCTV camera with 4-CIF has a resolution of 704 x 576 pixels, which is about 400,000 pixels. But a camera that has 2560 x 1920 pixels provides 4.9 million pixels; more than 12 times the pixels of a 4-CIF device. This means that one megapixel camera can provide as much detail as 12 4-CIF cameras.
This additional detail is extremely valuable for several reasons. First, better quality means better evidence. Very often, suspects are seen on 4-CIF video, but it is difficult to identify them positively. With megapixel cameras, excellent detail provides convincing evidence in court.
Another benefit of megapixel is that facilities need fewer cameras (compared to traditional cameras)—often only half as many. And although the individual cameras cost more, megapixel installations require far less electrical/data cabling and labor. The ability to cover large areas with fewer cameras is especially important in facilities like convention centers, airports, shopping centers, and sporting venues where there are large open areas and crowds.
High def CCTV also brings an end to the fixed vs. PTZ (pan, tilt, zoom) dilemma. When cameras are capable of PTZ, events and people can be missed because the camera happens to be pointed in the wrong direction. For example, if a security operator zooms in a camera on a woman who falls down, he may miss seeing someone else take advantage of that distraction to steal another woman’s purse. And when the purse snatcher is caught, it may be difficult to prosecute him because there is no evidence to dispute his claim that he found the purse.
With megapixel cameras, it is possible to keep the camera fixed to record the entire view in high definition while still allowing operators to zoom into areas of the image for greater digital detail. This preserves the overall scene for later review while still allowing operators to focus on areas of interest. This is extremely useful in forensic analysis, where a seemingly unimportant background detail can often be the clue that cracks a case.
Now for the challenges. Because high definition video contains so much detail, it also contains much more data than traditional digital video. This means the network and storage must be able to handle the huge flood of data. Network upgrades or a completely separate network just for high definition video may be necessary.
This all depends on many variables, including how the network is designed and how large the video is. Megapixel encompasses many cameras that range from just over one megapixel to cameras like Avigilon’s (www.avigilon.com)
16 megapixel monsters.
Facility managers (fms) who need to run new network cabling for high definition video (or to install new cameras) should be aware the cost is negligible, but necessary (new cable will be needed for any kind of camera). But where there is an existing digital surveillance network, it could mean installing a second cable system just for high definition video, which can be costly.
One vendor, Pixel Velocity (www.pixelvelocity.com)
, has a technology that allows very large (5-megapixel+) cameras to operate on existing digital surveillance networks by placing local servers in closets near the cameras and recording full megapixel video there. Back at the command center, operators can see the whole image at 4-CIF resolution but can also digitally zoom into any region of interest to get the full megapixel resolution for that area. They can digitally move this zoomed window throughout the entire view.
Another vendor, IQInvision (www.iqeye.com)
, uses advanced compression based on the H.264 codec to allow 1.9 megapixel streams over networks at manageable data rates. These techniques allow megapixel cameras to be used with existing networks, both hard wired and wireless.
H.264 is a video standard that provides high video quality at much lower bandwidth than previous video standards. By using advanced techniques, H.264 can send a video feed that requires as little as half as much bandwidth as previous standards. This is especially valuable in megapixel video cameras, where the amount of bandwidth required can be extremely high.
As for storage, megapixel data is very different from traditional video. Because of the image sizes, cost/benefits will need to be made by fms who may end up with terabytes of storage with megapixel cameras. The key decision is how long to store the video. For many organizations, one to two weeks is sufficient. But many organizations are opting for much longer retentions to help counter insurance claims or provide forensic evidence for law enforcement. Consequently, some retain video for months, or even up to a year. If this is the case, fms will probably need to plan a process of archiving to DVD or digital tape, because hard drive storage for all that video would be a significant cost.
So why do I say high definition video could be the magic bullet that transforms the way we think about video surveillance? Because high def video just might motivate fms to replace their analog CCTV systems. The majority of surveillance cameras in the U.S. are still analog, and many organizations have been hesitant to replace them with traditional digital video camera systems.
Many fms cannot justify the cost for digital video when it does not offer significant functionality. They say that the quality is better, and digital video can be accessed across the network, but these are often not enough to warrant replacing an entire CCTV system. High definition video, on the other hand, offers a quantum leap in quality, fewer cameras for better coverage, as well as all of the advantages that traditional digital video has to offer.
Condon, a Facility Technologist and former facility manager, is a contributing author for BOMI Institute’s revised
Technologies in Facility Management textbook. He works for System Development Integration, a Chicago, IL-based firm committed to improving the performance, quality, and reliability of client business through technology.