Seeing into the heart of darkness isn't as hard as you might think, thanks to technologies ranging from thermal imagers to short wave infrared.
An old chinese proverb says that it’s better to light a candle than to curse the darkness. Many companies stumped by the challenges of achieving surveillance in the darkness may be tempted to curse their predicament, but there are several tools—far better than candles—that they can use to attain the night vision they seek.
There are imagers that detect temperature changes and lasers and light beams that can be shot out to illuminate large areas. There are also camera sensors that can produce images by using a type of atmospheric energy not visible to the human eye. Here’s a look at some of these technologies, their strengths and weaknesses, and a few examples of applications where they are proving effective.
Thermal imaging technology allows cameras to capture anything that gives off heat. They use the infrared spectrum and, therefore, require no light. Thermal cameras are essentially monitoring temperature changes in the field of view, according to Christiaan Maras, Eurasia marketing manager for Portland, Oregon-headquartered FLIR Systems, Inc.
Since the human body gives off heat, thermal imagers are effective at deciphering whether there are trespassers in an area. And more sensitive thermal imagers let users know the difference between a person and an animal.
There are both cooled and uncooled thermal detection options. According to FLIR, cooled thermal imaging cameras are integrated with a cryocooler that lowers sensor temperature, which allows the camera to reduce the thermally induced noise in a picture, making for clearer images. Cooled systems are more sensitive to temperature differences than uncooled, and tend to be used in longer ranges, but they are much more expensive, and their cryocoolers need rebuilding after about 10,000 hours of operation.
Uncooled thermal cameras do not use cryogenic cooling. These systems tend to be appropriate for applications in which users do not need to detect something past about three miles, explains Maras. Uncooled thermal imaging systems also need less maintenance than infrared-camera systems with illuminators because they don’t have bulbs that may need to be replaced.
A thermal imaging system, whether cooled or not, provides only outlines of the heat contrast on an individual or object, rather than the detailed picture CCTV cameras normally provide. “It can just say, ‘I think that’s a person running around doing something bad,’” says Product Marketing Manager Willem Ryan of British Columbia, Canada-based Extreme CCTV. He calls thermal imaging a “seek and detect” technology.
Integrator Roberto Pablo, applications engineer for RFI Communications and Security Systems, says that thermal imaging cameras are, therefore, generally recommended for long-range needs where intrusion detection, not identification, is the goal. He cites border patrol as an example: “I don’t need to identify [people crossing the border] but I just need to know there’s somebody out there crawling, there’s a heat signature, and if I can identify that between human and animals, then…my officers can be alerted and say, ‘Hey…there’s somebody out there trying to cross the border.’”
For the same reason, thermal imagers are effective in fog and types of inclement weather where other camera options might have problems getting an adequate image or making any sort of detection. Thermal cameras also can be a good supplement in broad daylight because, unlike normal cameras, they can detect a person trying to hide in shadows, bushes, or a forest.
Maras points out that thermal imaging cameras are “passive” systems, because they are not beaming any types of lights or lasers out at the field of view.
FLIR has provided thermal imaging cameras at the London Eye, a cantilevered observation wheel that provides visitors a view of London’s landmarks and receives an average of three million visitors a year; at France’s Port of Calais, where the cameras detect people trying to illegally cross the English Channel; at Copenhagen Airport, where the cameras search for unauthorized persons in a secure area; and numerous other locations.
Maras says the prices on thermal imaging cameras have come down quite a bit over the past few years due to increased demand. FLIR’s most economic option is around $4,000, says Maras.
While thermal imaging is a passive tool for viewing the infrared spectrum, light emitting diode (LED) illumination is an active technology. The diodes emit near-infrared spectrum light waves, which are invisible to the naked eye, directly onto the area in view. The resulting image is like that captured by a regular camera taking pictures of any illuminated area.
One company that has pioneered night vision illuminators using this technology is Extreme CCTV, now a part of Bosch Security Systems. The company is constantly pushing the envelope with regard to what the technology can achieve. Among the most recent iterations is something it calls Black Diamond technology, which counters a natural distortion that can happen because of the way the light is traditionally projected onto the field of view from the illuminator.
Black Diamond pushes the light out so that no section of view is over- or underexposed, thus avoiding a common problem in LED illumination, says Ryan. The illuminators can be used as part of integrated Extreme CCTV and Bosch camera units or can be bought separately as standalones and added to cameras from other companies.
One can definitely see the difference when using the Black Diamond versus other LED technology, says integrator Pablo. The entire field of view is truly illuminated evenly, he says.
Canada-based Mark Anthony Group, Inc., which manufactures and distributes wines and beverages such as Mike’s Hard Lemonade, uses the system in its nighttime surveillance applications. The Extreme CCTV illuminators make it “literally look like high noon at night,” says Keith Braham, the company’s security systems manager. He notes that there is no blooming, or whiting out of the image, which sometimes happens in LED illumination.
Braham began using Extreme CCTV’s LED-equipped cameras in 2008 at his company’s Vancouver location in part to ensure that security guards are doing patrols at night. He says the technology is also installed at the CEO’s property. He plans on installing additional cameras with the illuminators in the company’s vineyards.
LED illumination does have its weaknesses. The first problem is the range. Ryan admits that while some of the illuminators can reach more than a quarter of a mile, they are not necessarily the best tool for long range identification. “It has the same properties as visible light in the sense that range is going to be an issue, in terms of if you do need to see miles and miles away, active infrared is not for you. Because that’s not what it’s built to do,” he explains.
To its credit, Extreme CCTV has worked over the past few years to provide clear guidance to end users about the range within which its illuminators and integrated systems are most effective. The company bases the assessments for its integrated solutions on criteria devised years ago by John Johnson for the U.S. Army Night Vision Lab.
Johnson’s criteria breaks down the levels of surveillance to detection, classification (distinguishing between human and animal, for example), recognition (of threats), and identification (of a specific individual). The criteria are known as DCRI. Ryan says his company defines distances based on those parameters, so if a user needs to be able to recognize a person 150 feet away, the criteria can help them select the right equipment for the job.
For standalone illuminators, it’s harder to apply DCRI criteria because the range of quality images depends in part on the camera. In those cases, Ryan says Extreme CCTV provides the range for which the illuminator can ensure a high-quality, usable image. Ryan adds that while infrared’s light qualities provide for good resolution, the illumination gets reflected and refracted in the same way that visible light does so it might not be effective in fog, sand, or snowy conditions.
Another problem is that the LED bulbs can go out or get dimmer as time goes on. But Ryan says Extreme CCTV has come up with a technology to combat that as well, called Constant Light, which monitors the LED voltage output and ensures that bulbs are providing the same brightness throughout the life of the illuminator.
LED illuminators can be used for all different types of applications and thus have wide-ranging price points.
Prices on some of Bosch’s popular products include around $1,600 for an illuminator that’s used for such applications as utility and perimeter surveillance, and about $3,000 to $5,000 for IP infrared imagers that can be used for anything from high-end residential perimeters to ports and critical infrastructure.
Continuous Wave Lasers
A fairly new alternative in night vision is a nonpulsing laser system. One option comes from Atlanta, Georgia-based Vumii Inc.’s continuous wave near-infrared laser camera system, the Discoverii. It is an active illumination system, but instead of using LED illumination, the Vumii device projects a continuous wave laser that does not pulse.
Some of the traditional laser options for nighttime surveillance are either very weak lasers or extremely strong, expensive range-gated systems that necessitate pulsing lasers, according to Vumii’s president, Randall Foster. Foster says Vumii’s cofounder, Micky Tamir, was one of the developers of range-gated laser systems several years ago.
“One of the unique breakthroughs is our ability to spread this energy uniformly in an area and then control that cone by its diameter, its intensity, and its focus,” explains Foster. Basically, this makes it possible to direct the laser light to exactly the area the camera needs to capture. The laser is essentially acting as the light source for traditional CCTV video, much like the LED illumination acts as a light source.
The major advantage that Discoverii has over LED illumination is that it can capture a picture with sufficient detail to enable identification of intruders over a greater distance. Ian Francisco is an integrator and CEO of Unlimited Technology, Inc., which recently entered into a strategic partnership with Vumii after using its camera units in various projects, such as critical infrastructure. He says the model that has the longest range, called the Discoverii 3000, can provide identifiable-quality video in the dark at a range of almost 9,000 feet. “There’s not another camera on the market that will even touch it,” he says.
Independent consultant Jones agrees, saying, “Vumii’s Discoverii has extraordinary range and is an important technology for areas such as critical assets, stakeouts, and border protection.” She notes that “Extreme CCTV is useful for outdoor protection but used in areas that don’t require the range Vumii offers.”
Foster says Discoverii units, which include a camera and a laser enclosure, are often matched up with another system, such as thermal imaging, which can detect movement. Once the first system detects movement, Discoverii can zoom in and concentrate its lasers on the area that needs closer attention.
A disadvantage to Vumii’s system is that it is quite expensive. Foster says the Discoverii 1000 unit, which has the shortest range, retails for about $58,000, while the longest range model runs about $125,000.
However, Terry Lyons, who works in security for Aqua America, a water utility group, says that he has actually saved money with Vumii. He has installed Vu-mii’s Discoverii cameras at dams, reservoirs, and other locations, and says one Vumii camera can replace up to five other cameras. Additionally, the setup doesn’t need any type of light or multiple camera infrastructure. Lyons says he was using infrared imagers before, but the quality of the video was not good enough.
Although Vumii’s laser is less powerful than range-gated lasers and does not need to be on a pulse, it is still a laser and does come with safety precautions. The laser system is filed with the U.S. Food and Drug Administration’s Center for Devices and Radiological Health as a Class 1 system, says Foster. Class 1 is the safest level.
Vumii’s lasers have an eye safety range of about 50 feet, says Foster, which means that someone looking into the beam at this short range could have retinal damage. The units have specific installation heights. Sensors detect if anything is coming within the safety range and turn the lasers off if needed, and the unit also has locks that don’t allow it to turn too far down and break the safety range.
One of the cameras used in Lyons’ applications is near a highway, he says. In that instance, there are settings that prevent the camera from sending lasers into oncoming traffic.
Vumii is coming out with a new 500-meter model, according to Foster, which will not have safety-range issues due to the lower power of the laser. It will have a more economical price and will be geared toward mobile use, such as on low-flying aircraft.
Short Wave Infrared
Another fairly new company—NoblePeak Vision of Wakefield, Massachusetts—has an entirely new night-vision technology developed by the company’s founders, Clifford King and Conor Rafferty. King and Rafferty began using the technology when they worked at Bell Laboratories, and they later realized it would be valuable for image sensors.
The technology involves altering the CMOS sensor, which many CCTV cameras use to process images. The technology allows the sensor to capture images using a light source only visible on the short wave infrared spectrum (known as SWIR). The light source is commonly called “night glow.” It comes from the hydroxide ions that are floating in the Earth’s atmosphere.
Night glow is “untapped in commercial markets,” according to Phil Davies, NoblePeak’s vice president of marketing. Davies says the energy is always there, but it’s at a wavelength that normal CCTV cameras and thermal imagers cannot see.
The system is passive, unlike the active LED illumination and Vumii’s active laser system. The picture that Noblepeak’s system yields is good enough to be used for identification purposes, says Davies. The light is coming from the atmosphere rather than being beamed out by any type of illuminator, so the range at which the system can capture a good picture may be limited only by the range of the camera the sensor is in.
Moreover, the atmospheric light source could be better than the sun’s light, Davies says, because there won’t be any shadows, due to the fact that atmospheric light is all around.
Another advantage Davies envisions is that cameras using the sensor could function as normal CCTV color cameras during the day and switch to detect nightglow and be monochrome at night.
The company has garnered international attention. It won the Global Security Challenge 2007 Grand Final as the most promising technology start-up. Various camera companies are scheduled to start using NoblePeak’s test cameras with the CMOS sensors this March. The company’s goal is to sell camera cores that include the sensors directly to camera manufacturers.
Jones called NoblePeak’s technology “The one system that I have seen that could potentially revolutionize the industry.”
Davies foresees homeland security being the first market for the technology. “Things like the Secure Border Initiative or protecting military bases where you don’t particularly want to light everything up and it isn’t feasible to run lights everywhere and you also want to be a little bit covert, our technology plays extremely well,” he says.
Initially the price per camera may run as high as $10,000. However, the price will go down to as low as $2,000 for some models after a few years, Davies predicts.
“One [camera] system is the ideal as the costs to buy and own come down and you can have one system that works both for day and night. If the technology from NoblePeak works the way they say, it holds the most promise,” says Jones.
Criminals have always sought to take advantage of the dark. But developments in the fields of imaging and camera technology are shedding light on the problems of nighttime surveillance, making it easier to force criminals out of the shadows.
Laura Spadanuta is an assistant editor at Security Management.