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.