Larson Electronics LLC

Benefits and Applications of Thermal Monitoring Solutions for Security and Surveillance

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Courtesy of Larson Electronics LLC

Advancements in technology have enabled criminals to become less predictable and more invasive. But this phenomenon works both ways, allowing law enforcement and military groups to use technology to their advantage when monitoring illegal activities discreetly.

In the field of security and covert operations, thermal detection is becoming increasingly common. With thermal cameras, infrared (IR) illuminators and light towers, agents no longer have to succumb to the drawbacks of operating in unfavorable, nighttime conditions. These days, businesses are also using thermal cameras to watch over commercial spaces outside of operating hours. Such systems can even be connected to a network for remote viewing from a safe location.

Thermal Detection and Heat Signature

Generally speaking, security monitoring systems can be broken down into three stages: Detect, Notify and Identity. At the initial stage, thermal cameras are used to uncover disturbances or unwanted intrusions. The units are able to accomplish this by collecting electromagnetic radiation formed by objects. Unlike mainstream cameras, thermal cameras are specifically designed to perceive radiation up to 14,000 nm – with high wavelength ranges outside of the visible light spectrum being invisible to humans.

The second component that thermal cameras rely on for detection is heat signature. All organic and non-organic objects (all objects with temperatures above absolute zero [i.e., -273° C or -459° F], including ice) emit heat that comes with a specific amount of IR radiation. Thermal cameras pick up on such elements to create a clear image of the target area. Due to its reliance on IR radiation, the units can detect intruders dressed in camouflage or all black.

A developing trend in thermal monitoring solutions is the use of invisible thermal fences. By setting up a geo-referenced perimeter that cannot be seen by humans (note: not a physical fence structure), surveillance groups could automate monitoring (cameras activated when a trespasser unknowingly “sets off” the thermal fence) and approach offenders with their guard down, thus avoiding aggressive or potentially fatal confrontations. A huge advantage to thermal fencing is its customizable perimeters and rules. For example, one could create temporary exclusion zones when part of the target location is in use or occupied by trusted individuals.

Leveraging IR Lights with Security Camera Surveillance

The sight of security cameras and bright lights are usually enough to deter criminals from trespassing on private property, committing theft, vandalism or random acts of violence. From another perspective, using a surveillance system with strong luminaries that emit visible, white light could backfire. By knowing exactly where the cameras are located, lawbreakers could easily circumvent the peripheral range of the units and avoid getting detected.

For a covert approach to security monitoring, one should leverage IR illuminators. Humans can’t see IR light, but most mono-CCTV and “true day/night” cameras (more on this later) can. In application, IR illuminators invisibly “light up” the target location, making security cameras more effective. Furthermore, it can do this in complete darkness, so you could install the system in discreet areas that are undetectable by intruders who aren’t familiar with the location. When setting up an IR-powered security camera system, it is crucial not to point IR illuminators directly at the camera. This will cause the recording to “white out,” resulting in blocked, low quality images.

The benefits of incorporating IR illuminators with surveillance systems are numerous. IR light is capable of penetrating haze, snow, pollution, high humidity and some obstructions. This is especially applicable to monitoring targets in outdoor locations and environments with low visibility conditions. Most IR illuminators rely on LED technology for illumination. The advantages of using IR LEDs include the following: low energy consumption (up to 70 percent in energy savings), instant toggling (on/off), lengthy lifespan (up to 50,000+ hours) and sturdy, solid-state builds (less prone to malfunction or premature failure). CCTV camera footage with IR illuminators typically have less glare from external light sources, due to lower contrast ratios from “well-lit” dark spots.

IR 850 nm (semi-covert) vs. 940 nm (invisible)

IR light comes in several different invisible wavelengths. It is common knowledge that IR bands 780 nm or above cannot be detected by humans; and “true day/night” security cameras are sensitive to this range. Most commercial IR illuminators emit 850 nm bands, which is almost invisible to humans. During operation, criminals can easily detect such surveillance systems via a red glow from the illuminator. Because of this, using IR 850 nm only offers “semi-covert” benefits for security.

By comparison, IR 940 nm is fully invisible to humans. Looking at the illuminator, one would be unable to distinguish whether or not the luminary is on. As a result, illuminators that emit IR 940 nm bands are specifically suitable for “fully covert” security operations.

Before you swap out all of your IR 850 nm illuminators with 940 nm models, there is something you have to take into consideration. “True day/night cameras” are sensitive to IR bands – but the level of sensitivity varies, depending on the wavelength of the light. IR 850 nm is almost twice as efficient, compared to IR 940 nm, with the latter resulting in lower image quality (hence, surveillance systems that use IR 940 nm have shorter distance specifications). To fix this issue, one must utilize an IR illuminator with roughly double the power or revert to using lights with lower IR bands.

Lastly, when using IR illuminators with security cameras, it is essential to ensure that the cam supports “true day/night” functionality. This feature allows cameras to “see” light produced by IR luminaries via an IR cut filter that can be removed mechanically in low light environments. As a general rule, most commercially available cameras are not as sensitive to IR 940 nm bands.

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