Surveillance System Technology Trends
The first transatlantic cable laid at great expense in the mid 1950s could carry only 36 telephone conversations at a time. That problem of bandwidth—how much information can be sent over the communication medium at one time—and the corollary problem of how to store it at either end remain vexing today. But technological advances are enabling affordable solutions. And those innovations are finding their way into security systems.
Surveillance systems have benefited greatly from such progress. One area concerns new low-bandwidth ways of sending video back to a monitoring center. For example, the use of a compression format called H.264 cuts bandwidth use by up to 90 percent, notes Arecont Vision’s Scott Schafer.
Another concerns ways in which video data can be recorded “at the edge” where the camera is, reducing the need for costly network bandwidth. More companies are putting SD cards in cameras for storage at the edge thanks to dramatic declines in the costs of such cards. While one gigabyte cost about $150 in 2004, today you can pack a 32 GB SD card in a camera for under $40, says Fredrik Nilsson of Axis Communications.
Companies are also developing systems that carry out the analytics at the edge, so that the HD video doesn’t have to be streamed to be analyzed. A relatively new company called Innovative Security Designs has gone even further, giving its edge cameras the ability to form a sort of sci-fi collective hive mind that allows them to write video to each others’ hard drives for backup, all on the edge. They also check on each other, and they can phone in an alert if one camera has problems.
Where it is necessary to stream back video, companies have creative ways to cut down on the data load without cutting out the image information that those watching the video will need. OnSSI and Salient each have their software recognize the resolution of the viewing monitor at the receiving end and send only the data needed for a good picture. Salient says that this makes it possible to use an existing 4G network. CheckVideo takes the approach of only sending 10-second clips when there is an alert-level event, which also allows use of just a cell phone network.
Some companies years ago figured out that you could just send frames where there had been motion or change. But now DVTel has put a new twist on that. Instead of sending the entire frame or the video of the change, it just tells the computer at the other end what the change has been in mathematical terms and the computer moves the pixels on its end. That one innovation could help a city with 7,000 surveillance cameras save $5 million in storage costs, says Paul Smith of DVTel.
These are just some of the improvements that are making surveillance systems more affordable by overcoming the traditionally daunting bandwidth and storage issues.
