Video surveillance is a powerful tool, especially when price is not the main deciding factor behind what is purchased. While some camera systems cost less, the overall effectiveness is markedly less than when image quality is made a priority.
Those who misguidedly purchase low-quality cameras expecting top-camera results are usually disappointed in the end result. The most common reason for dissatisfaction in this regard is a general lack of image quality that ultimately jeopardizes the overall mission. The bottom line is you usually get what you pay for.
A good example is when it’s necessary to read a license plate on a motor vehicle. Without a high-resolution image, it’s nearly impossible to obtain a clear, concise plate number due to distortion on digital zoom. Also consider the need to derive facial detail to identify one or more individuals.
“Since 9/11, there have been many civil rights-related questions raised about video surveillance. What has been discussed less frequently is the actual quality of the video displayed and recorded. A simple question might be posed, ‘Why do even the most basic cell phone cameras capture higher resolution images than the average video surveillance system?’,” writes Peter McKee, author of “Why the French Spot Terrorists Better Than Americans,” on Officer.com (January 2008).
The problem with low-resolution surveillance cameras is such evidence may fail to achieve a conviction in a court of law. At the same time, there are applications where a conviction is not the primary goal, but rather general safety and security through real-time observation and on-site response.
As with any other project, it’s important to examine the purpose of the proposed video surveillance system, especially if it is to be used in public spaces. The ultimate goal should then be weighed against budgetary limitations in order to come up with the right combination of cameras and head-end equipment. Getting the most for the least is still a part of this process.
The need for high resolution
The better the camera, the more likely the culprit can be identified when a theft occurs. When identification is possible, so is restitution.
“It is my opinion that high-resolution technology will eventually take over the video market entirely,” said Erron Spalsbury, account manager, 3xLogic, Westminster, Colo.
“For a good face shot, we need the camera to be close enough to see who it is. With the new high-definition cameras, these wide angles work by merely having more pixels and higher definition. You need the additional pixels so you have the ability to zoom in, thus giving you a much cleaner image,” he said.
For many years, according to Spalsbury, the standard has been cameras that do not always provide the quality needed to effectively identify the bad guys. When price is an issue, many clients default to the same technology they have used since the 1960s. Despite the fact that they continue doing things the same way, they expect a better outcome for some reason, which simply isn’t going to happen.
By using software capable of providing digital zoom, it is possible to select portions of the image for close analysis. However, digital zoom leads to pixelization. With higher resolution, images have better detail and a better chance to identify the criminals.
When high-resolution images are required, the industry more often thinks of Internet protocol (IP) cameras, which are based on megapixel technology. But there is an alternative that uses high--definition closed-circuit television (HDcctv) technology.
“There are semiconductor advances in image capture, lenses and sensor technology that have come together to yield high-quality surveillance,” said Todd E. Rockoff, executive director and chairman of the HDcctv Alliance of Sydney, Australia.
HDcctv uses a digital transmission format that transforms an analog signal into a digital equivalent, which is sent down a standard coaxial cable at lengths up to 100 meters. Subsequent releases can be expected to render a transmission distance of three times that.
“The HDcctv roadmap provides for 300m uninterrupted coax cable runs following after up-the-coax control and power, anticipated as version 4 of the HDcctv specification,” Rockoff said.
According to Mark Oliver, director of product marketing with Stretch Inc. of Sunnyvale, Calif., HDcctv works by not compressing the data, essentially eliminating latency.
“This is a digital format that sends uncompressed camera images down a coax cable at about 2 gigabytes per second. When it gets to the other end, it converts it back to an analog signal,” Oliver said.
The fact that the camera signal makes the trip without compression is important because image latency lessens the quality and contributes to the end-user’s inability to use stored images for anything other than a historic view of events.
“Because you never actually compress the signal, you don’t lose the quality,” Oliver said. “By not compressing the signal, we do not encode latency. We digitize the signal and send it along as base band video instead of in a compressed form.”
COLOMBO is a 35-year veteran in the security and life safety markets. He is director with FireNetOnline.com and a nationally recognized trade journalist in East Canton, Ohio. Reach him at firstname.lastname@example.org.