Thermal imaging may seem like something out of science fiction, but it has its roots firmly planted in history. In the late 19th century, American astronomer Samuel Pierpont Langley created a device called a bolometer, a device comprised of metal plates, a bridging circuit, an electromechanical measuring instrument, and a liberal application of soot. This gadget could detect minuscule changes in temperature, and between World War 1 and World War 2, it would later see the British develop it into a visual technology for spotting enemy aircraft. However, thermal imaging wouldn’t achieve broader adoption until that the late seventies and early eighties.
Today, thermal camera systems have gotten adopted in public-safety fields other than the military. In this article, we’ll discuss what these cameras are, how they work, the fields that use them, and specific applications.
What are Thermal Imaging Cameras?
Most people intuitively know what thermal imaging cameras are simply from the name. Indeed, their function is right in the title. They detect heat and display it on a screen so that we can see it. But thermal imaging camera systems have a lot more going on than you might imagine — and face certain limitations that aren’t immediately evident.
The human eye is a marvelously engineered organ, but it doesn’t capture everything that strikes it. In fact, we only see a small part of the electromagnetic spectrum that reaches us. Visible light represents a very small slice of the spectrum, surrounded on one side by ultraviolet, X-rays, and gamma rays and on the other by microwaves, radio waves, and long waves. Right below visible light lies infrared radiation, a near visible kind of wave that’s emitted by things that are hot.
In the introduction, we mentioned Samuel Pierpont Langley and his bolometer, which could detect gradations of infrared radiation. His invention got refined over the years into a tinier device called a microbolometer. Microbolometers have been integrated into camera-like tools that have lenses. A microbolometer can suss out thousands of infrared-radiation data points, and it uses those to create a “picture” (so to speak) called a thermogram. This is a real-time, moving representation of the data as it strikes the sensor. However, understand that a thermogram isn’t a real image. Instead, the thermal camera interprets the information it receives in a picture form, showing the differences in heat through arbitrarily assigned gradations in tone or color. (Some thermal imaging camera system manufacturers choose to produce monochrome cameras, but most use the familiar looking rainbow-hued system popularized in movies and TV.
There’s a second kind of thermal imaging option called direct detection. This type of thermal imaging senses photons directly, resulting in longer detection ranges. However, they also require significant cooling to function properly, are much larger, require much more maintenance, and carry a significantly higher price tag.
Before we continue on to examples of how thermal imaging cameras have come to benefit the common good, we need to clear up some misconceptions as to how these devices work. Some people conflate them with night vision, which had led to unfortunate monikers such as “infrared night vision camera.” Yes, it’s true that thermal imaging cameras can “see” in the dark. But they aren’t night-vision devices. Those work by capturing and amplifying ambient light, and they have an entirely different array of capabilities and drawbacks.
Finally, popular presentations regarding thermal imaging have introduced all sorts of inaccuracies. For instance, many individuals passingly familiar with the technology believe that it can see through walls. That’s less than accurate. If something behind a wall causes the temperature to jump an appreciable amount (think of vermin scuttling through crawl spaces), then a thermal camera might be able to detect it. The same holds true for oxidized metal, concrete, and thin plastic. Also, any smooth or polished materials (e.g., glass, polished metal) will reflect heat.
Though not exactly ubiquitous, thermal imaging cameras have proliferated in recent years and seem set to continue to do so. Analyzing the competitive landscape in 2020, research firm Fortune Business Insights anticipated that the market for these devices would compound nearly 8 percent annually. But how are these cameras being used and how do they help the common good? Read on to learn more.
For local law enforcement agencies
Thermal imaging is a natural fit for law enforcement the world over. Not only does it help them identify potentially hidden threats, it also can aid in performing routine tasks. Some of the ways in which police employ thermal cameras include:
Fugitive Searches. When inmates break out of jail or perpetrators attempt to flee the scene, staying hidden is high on their list of priorities. Many crimes occur at night, too, and the cover of darkness can frustrate attempts at apprehension. Thermal imagining plays an important role in locating suspects when they don’t want to be found — particularly when employed from a helicopter.
Surveillance. Similarly, surveillance seeks to stop crimes before they start or gain evidence for future court actions. Law-enforcement professionals enjoy greater rates of success when they can follow potential drug deals or illegal exchanges of money under the cover of darkness or from a distance.
Hidden Compartments. As we mentioned in our previous section, thermal cameras cannot “see” through solid objects; the best they can do is to see if an object behind a barrier has transmitted heat through it. However, thermal imagining has experienced some success in detecting contraband stashes secreted away in surreptitious spots.
Disturbed Surfaces. Piecing together evidence isn’t as simple as connecting the proverbial dots. Even before authorities gather proof, they have to first find it. Thermal cameras may sometimes point them to applicable areas (i.e., sections of disturbed soil).
Evidence Retrieval. A related use includes the retrieval of evidence that has been disposed of during a flight incident. It much easier to find a gun that’s been tossed away or a suspicious package when it still contains some of the suspect’s heat.
An April 2000 article in the Los Angeles Times declared, “Perhaps the best advance in fire equipment in the last 25 years — and the most expensive — is the thermal imaging camera.” That statement might not make much sense at first glance. Firefighting invariably involves heat, and what advantage can a thermal imaging system offer with a burning building? Quite a lot, actually. In general fire scenarios, thermal cameras can help first responders find occupants even through smoke. Additionally, they can aid with:
Overhaul. Defined as the process of determining any extension (or spread) of a fire, overhaul is one of the last things a firefighter addresses — and one of the most important. If the overhaul process isn’t properly conducted, the seeming end of a fire can become a wild new blaze, leading to further property damage and potentially loss of life. Thermal imagining solutions let firefighters identify ongoing hot spots.
Hazmat Responses. Firefighters do more than just fight fires. They also can be called upon for hazardous materials cleanup. Sometimes, though, it’s difficult to identify spilled substances with the naked eye alone. Because these chemicals will normally have a different temperature than the surrounding environment, thermal cameras can ensure first responder safety and a successful cleanup.
Outdoor Search and Rescue. When firefighters find themselves searching for an individual, it usually involves situations far different from those faced by law enforcement. Still, the same technology that aids the police in apprehending criminals can help first responders save the injured, ill, and elderly.
For the military
The first practical usage of thermal imaging occurred in a military context, and it’s no surprise that martial usage continues today. Obvious roles for thermal imaging include identifying troops, vehicles, and aircraft, but there are others, too, such as:
Military Base Protection. Security professionals often recommend the installation of lighting systems in order to safeguard sites. However, such options can introduce vulnerabilities in a military context. Thermal imaging provides much of the same benefit, allowing sentries to scan darkened areas and detect presences along a base’s periphery.
Vehicle-Mounted Sights. Military vehicles face unique challenges on the battlefield. Positioning is paramount when both engaging the enemy and shielding against exposure to fire. Smoke and inclement weather can reduce situational awareness, but thermal imaging helps restoring it, letting vehicle crews know more about their surroundings.
Infantry Equipment. Similarly, on-the-ground soldiers also benefit from enhanced understanding of their combat context when particulate matter obscures their vision. Technology such as thermal binoculars and thermal sites have become common for many branches of the military.
Land Mines. Traditionally, soldiers have used metal detectors in order to find and disarm land mines. Given the rise of nonmetallic mines, though, thermal imagining employed by a drone helps identify these explosives.
Intelligent transportation systems
One surprising application of thermal imaging involves the field of traffic control and optimization. Clogged highways can impact a community’s productivity and even lead to loss of life in some sad scenarios. Ensuring that traffic continues to flow smoothly is of utmost importance, and thermal imaging can help. How? Consider that it serves as an important tool when managing:
Advanced Signal Control. Injuries and accidents involving pedestrians, bicyclists, and public transportation exact a steep price both in terms of human life and operational efficiency. Thermal imaging can serve as a stopgap, a buffer that helps mitigate against incidents and injury. By integrating signals (such as stop lights and crosswalk lights) with thermal cameras, intelligent transport systems can adjust stop light functionality to optimize traffic flow. While this protects foot traffic, it mitigates against unnecessary idling for automobiles.
Traffic Data Analysis. A 2013 study published in International Journal of Scientific & Engineering Research stated, “Traffic has become one of the main concerns in every city with the rapidly increasing number of vehicles on road. Traffic jams and sluggish traffic movement not only cause inconvenience to the general public, but also hinder the movement of emergency vehicles like ambulances, which may lead to detrimental consequences.” The authors of the study turned to thermal imaging to gather data that would allow for efficient traffic management, knowing that thermal cameras can continue to effectively function in inclement weather and darkness.
Tunnel Safety. One scenario into which thermal imaging naturally fits is that of tunnel safety. In the event of both minor or catastrophic incidents, thermal cameras can detect problems far before more traditional means. This allows authorities to better understands the breadth of specific situations and dispatch first responders more quickly, saving lives and quickly restoring the orderly flow of traffic.
The word “industry” covers an amazing range of businesses and field, including everything from oil and gas production to heavy manufacturing to chemical production to the creation of consumer goods. Thermal imaging is a robust enough technology to apply in all of these industries by:
Detecting Safety Hazards. Before electrical relays and wiring fail, their temperature spikes. Misaligned machinery leads to friction, which can also cause excess heat. Having a thermal imaging solution on hand can help head off these safety issue before they turn critical.
Prevent Potential Costly Failures. Relatedly, equipment also starts to generate heat as it begins to fail. When a drill bit grows dull, it generates more heat than it should while operating. Failing insulation around pipes will bleed more heat into the surrounding area. And when heat exchangers become blocked, a quick thermal scan will provide an accurate diagnosis.
Far from being a niche technology with limited application, thermal imaging has a vital role to play in all sorts of sectors. It ensures that operations continue unabated, potential failures get addressed before they come to pass, and human life is saved.