Intelligent video analytics purveyors have been on a public relations mission over the last few years. After much overhype and customer disappointment, companies that offer analytics are getting back to basics and trying to provide customers with the analytics they need (not necessarily the analytics they think they want) and to help them use the tools more effectively.
While it may not be possible to eliminate all false alarms, there are ways to decrease the number of alarms and to get more out of the analytics. In many cases, the most effective way to use analytics is in conjunction with other tools. For example, analytics can be combined with thermal imagers, as mentioned earlier, or other sensors like fence-shake alarms.
When the budget allows, redundancy can be set up wherein several triggers would have to go off for a video management system to consider a specific event an alarm, says Jessica Clark, executive vice president of Sigma Surveillance, which designs systems that combine various types of sensors and analytic tools to keep false alarms low. For example, a system might combine thermal cameras with sensors and analytics. If the sensor detects something, the analytic can provide further data about what it might be.
“In many high-risk critical-infrastructure power-generating utility-type of environments, we’re seeing a layered approach to security. So whether it’s ground sensors or fence-shake sensors, thermal-imaging cameras and video analytics, you’re typically seeing in those deployments multiple types of sensors as fail-safes,” concurs Whiteman.
Field of view. With higher pixel amounts in newer high-definition cameras, installations can be designed to use fewer cameras that take in a wider field of view, the theory being that the user can zoom in more given the higher resolution image. Not everyone thinks that this is the best way to use analytics, however, because it sometimes forces the analytic to try to interpret too large a scene.
Sean Ahrens, CPP, project manager with Aon Corporation, recommends having a more narrowly defined field of view to make analytics more effective. “The wider the field of view, the more objects, the less the video analytics is going to be effective. The more defined the field of view, now we’ve got opportunities to detect patterns,” says Ahrens.
Ahrens and others also advise that if there is a particular area you are concerned about, such as a fence line, you should do what you can to clear obstructions away from it. “The key thing is about identifying fields of view that are clear of obstructions, that are clear of opportunities for false alarm, such as...a flag blowing” says Ahrens. He notes that the system can be trained to filter some things out, but that takes time.
Whiteman agrees. “If you want to detect an intruder hopping a fence, you typically would want to have a clear shot of five feet roughly on each side of the fence. Where an analytic can get into trouble is if that fence is crowded by trees and brush, and an intruder hops the fence, the algorithm really didn’t have time to detect that individual upon the approach.”
Good image capture. Another important point with analytics is that the program can’t interpret information it does not get. That means the system first has to be properly configured with a good camera and the proper light so that a clear, sharp image of the scene is captured. It doesn’t matter what the analytic is if the camera image is not good.
Positioning. When designing the system, it’s also important to consider placement both with regard to lighting and how the analytic will function. Romanowich says that one good way to measure the real-world efficiency of a camera’s analytics is to see how it works when a target is moving toward the camera. It is easier for the system to detect an intruder walking across the path of a camera due to all of the motion. He says it’s important for manufacturers and integrators to be honest and specific about what the camera’s analytics can detect and what the range of detection will be. And that data can then be factored into how the system is designed for maximum performance in the field.
Height and distance are also factors to consider when placing cameras outside, and that’s especially important for analytics, says Whiteman, who explains that the system designer must consider the angle of view that will give the camera the proper perspective for viewing, say, a person approaching from 50 feet away.
Whiteman says that general surveillance cameras might be installed anywhere from eight to 10 feet up, but his company’s analytics use a three-dimensional depth perspective and require a higher mount for a comparable distance to differentiate between people, animals, vehicles, and other objects. Whiteman recommends a minimum mounting height of 12 to 15 feet for DVTel’s analytics camera to get a field-of-view perspective that might go out to 250 feet.
“We typically don’t want to be looking straight down at an object. And that’s what we mean by perspective,” says Whiteman. “So we typically like about a 20 degree camera angle to the target.”
Users must be familiar with the camera’s abilities so that they can determine the proper height and angle to achieve their objectives. However, Romanowich stresses that users must be aware that there can end up being a large space underneath the camera that remains unsurveilled. The system’s designer and installer should test different angles to decrease the space that is not visible to the camera. They may need to have another camera that is positioned elsewhere to capture that space.
By following these types of best practices in designing and installing outdoor systems, companies are getting better performance with analytics, notes Bill Bozeman, CEO of PSA Security Network. “Returns were as high as 60 percent two or three years ago. Our returns right now are miniscule; they’re approaching every other product we sell,” he says.
As various tools and offerings for outdoor surveillance improve, it’s still most important for integrators and end users to work together in finding the best offering for each specific installation. “There’s nothing like collaboration, direct collaboration with your customers,” says Clark. “That will always make you successful, if you have a good partnership with your customers, if you go into it not as a job but as a partnership in security.”
Laura Spadanuta is an associated editor at Security Management.