The great outdoors can be not-so- great for those who are setting up outdoor surveillance systems and attempting efficient perimeter detection. The equipment has to deal with weather, wind, possible tampering, and even the occasional wild animal or two. Additionally, there are trees, brush, pedestrians, and the toughest opponent of all—the darkness. Here is a look at recent trends in outdoor surveillance and perimeter protection and some best practices that can help to make the systems more effective.
The lack of light outdoors at night is a thorn in the sides of integrators. It isn’t always possible to install more lighting to make visible-light cameras work better in the dark. So security managers often turn to other tools.
Consultants, vendors, and integrators interviewed for this article kept coming back to one major factor: the dropping price of thermal imaging cameras. Thermal imagers read heat energy coming off objects. They provide a picture of the various heat energies in a field of view.
Thermal imagers are increasingly being used in conjunction with analytics and other sensors to reduce false-alarm rates. “Deploying analytics is no substitute for having lighting or infrared illumination. If you’ve got zero lighting at night, then the best use of analytics is linked to a thermal imager,” says John Whiteman, DVTel’s vice president of strategic programs.
In addition, some thermal cameras are used in conjunction with visible-light cameras, although it should be noted that visible-light cameras do need some sort of light or illumination.
Thermal cameras are best at the initial detection, especially when the lack of light isn’t the only impediment to visibility. “There are some scenarios where a thermal camera will always be superior. You can see through fog, through rain, behind leaves of a tree. You can never do that with a regular camera, doesn’t matter how light sensitive it is,” says Fredrik Nilsson of Axis Communications.
While other companies are jumping into the thermal market, FLIR Systems, long the dominant market leader, is attempting to stand its ground by improving its products. FLIR is now offering a higher resolution in its thermal cameras throughout its full portfolio. Bill Klink, FLIR’s vice president for security and surveillance, says that the resolution has gone up to a 640 by 480 pixel matrix. “When compared to a visible-light camera, that’s not exciting, because they’re obviously in megapixel land. For a thermal camera, that’s a big jump. It’s four times the number of picture elements [that] had been the standard in the industry, which was 320 by 240,” says Klink.
The increase in the number of pixels means that you can start with a wider field-of-view lens. (This might not be the best approach, however, if analytics are being used, as discussed later.)
“Basically it’s more economical. You can use fewer cameras to cover the same area,” explains Klink. He adds that the resolution decreases the need for longer- focal-length lenses. This is a plus because these lenses can get very expensive in thermal imaging due to the fact that the lenses are made of rare earth materials, not glass.
Color Night Vision
Advances are also being made in visible-light cameras that work in very low light situations. In the past, these cameras have primarily been able to yield only black and white images. Now that is changing.
FLIR recently brought one such camera to market based on technology developed for military use and obtained through the acquisition of a company called Salvador Imaging.
The camera uses a sensor chip known as EMCCD (electron magnified charge coupled device). “If you multiply the electrons, you boost the camera’s ability to see in very low light conditions, and with color. And that’s really the key point here. You get good color video in almost darkness,” says Klink.
However, the cameras do need a bit of light in order to work, since they are still visible-light cameras, and that can still be an issue in certain areas. Klink says that these cameras might sometimes be used in conjunction with a thermal imager or some type of analytic or sensor. The cameras will range from “under $20,000” up to about $50,000, depending on the type of camera.
The image chips inside cameras are getting much more sensitive overall. “The good thing, at the end of the day, is that technology in general is improving,” says Nilsson. “It used to be that you had to use a CCD, the more traditional sensor for an outdoor surveillance because they’re more light sensitive.
“But with very fast development of the CMOS [complementary metal oxide semiconductor] sensors,” he notes, “ they are increasingly becoming very good in low-light scenarios.” That advancement will continue as well, according to Nilsson. “So even regular cameras will continue to be better and better and more and more useful in outdoor environments as well.”
Outdoor surveillance, including perimeter detection, is also benefiting from advances in wireless technology.
“A lot of remote outdoor sites don’t lend themselves to physical infrastructure,” says Holly Tsourides, vice president of global sales for VideoIQ, who points out that if you’re installing miles down a fence line, it might be difficult to run traditional network cable. “You’ve had a lot of historical challenges there,” she points out.
But with the advent of digital cameras, she says, and with wireless subscription services becoming more affordable, it’s no longer necessary to run cables to or from the cameras.
To complete a robust surveillance system, “you’ve got to have video analytics, and you’ve got to have storage at the edge to take advantage of a cellular system,” says Tsourides.
According to Tsourides, surveillance cameras need the ability to store video at the edge so that the price doesn’t run up too high because of too much data being sent. (More on edge processing later.)