A lot of common technologies have found their origin in military applications. GPS for example was developed in the early 1970’s by the United States Department of Defense to guide missiles. When first integrated in cars for civilian applications, GPS was still a very expensive system. Today, a GPS system is installed in practically every new car. Today, another technology that found its origin in military applications is increasingly finding its way into useful civilian applications: thermal imaging. Whereas a normal camera is dependent on light to produce an image, a thermal imaging camera, sometimes also called an infrared camera, is able to pick up minimal temperature differences and convert them to a crisp thermal image. Contrary to other technologies thermal imaging can see in total darkness, needing no light at all (fig. 1).

The Beginning

The first thermal imaging camera for the military was developed in 1958 by Swedish company AGA, today known as Flir Systems (fig. 2). The first commercial infrared camera was developed in 1965. It was used for power line inspections (fig. 3). It took until 1973 until the first “portable” battery operated infrared camera was introduced. The technology used at that point in time required that the camera was filled with liquid nitrogen to cool down the infrared detector integrated in the system. 1997 saw the arrival of the uncooled thermal detector, also called microbolometer. This detector has no moving parts and is therefore less susceptible to breakdowns. It is also less expensive to produce, which allowed thermal imaging camera manufacturers to bring the price of their products down.

From Military to Industrial Applications

The microbolometer enabled the technology to make its way into commercial, industrial applications. The first to discover the benefits of thermal imaging were big production companies, who quickly discovered that thermal imaging can give valuable information about electrical equipment. Fuses, connections, cables, but also high voltage equipment like transformers, power lines and many more can all easily be inspected with a thermal imaging camera. The advantage is that thermal imaging can help maintenance managers to see an anomaly before a real problem occurs and as a result avoid costly breakdowns (fig. 4).
Within the same companies, Research and Development departments became enthusiast about thermal imaging technology. Thermal imaging cameras can be used early in a product design cycle. In the development phase, before going into mass production, appliances are thoroughly tested. Thanks to infrared, companies can shorten the development phase and start getting a rapid return on their development investments.

High Volume Production

Thanks to an increased use of thermal imaging technology by industrial companies, the first careful steps to so-called volume production could be taken. A few years ago, BMW, one of the major automobile manufacturers in the world, decided that it would implement a thermal imaging camera for driver vision enhancement into their top-of-the-line 7-series. Since a lot of accidents happen during nocturnal driving, BMW was looking for a solution to reduce this number of accidents.
Later on, the same “BMW Night Vision” module became also available as an option on BMW 5- and 6-series models. The high demand for this safety option allowed Flir Systems to increase production significantly. Today, for driver vision enhancement only, thousands of thermal imaging cameras are being produced by Flir Systems. This increased production volume led to a significant price reduction.
But volume production was not driven by consumer goods only. Unmanned Aerial Vehicles (UAV) are becoming more and more common in military and civil operations (fig. 5). These radio-controlled planes can be equipped with video cameras that are down-linked to a ground station. The military was the first to realize that thermal imaging allows the aircraft to fly in total darkness and detect targets through smoke and clouds. Civil applications quickly followed and today the same aircraft are also used to detect e.g. forest fires.

More Applications

With volumes going up and prices coming down, more and more applications for thermal imaging cameras have emerged.

Maritime
Ship captains need to navigate during the night as well. The costly vessel, its passengers, cargo and crew need to be protected. Captains can clearly see channel markers, shipping lane traffic, outcroppings of land, bridge pilings, exposed rocks, other vessels and any other floating object that might damage a ship when undetected in total darkness. Installed on a ship, a thermal imager can save lives as well. Finding a person that has fallen overboard within the shortest possible time-frame is of the utmost importance. Thanks to thermal imaging the drowning person can quickly be located and helped out of the water.

Firefighting
Firefighters have been using thermal imaging cameras for years in order to see in absolute darkness through smoke, as well as to detect hot spots in floors, walls and ceilings. The ability of thermal imaging cameras to see through smoke helps to saves lives. People can easily be located in a smoke-filled room. The ability to detect temperature differences of objects is vitally important to firefighters, who must often open doors that lead to fires, or who must identify the seat and extension of a fire quickly and reliably. Flir's handheld thermal imaging cameras have proven to be an excellent tool when used by experienced and well trained firefighters (fig. 6). 

Security and Surveillance
Thermal imaging is also making its way into more and more security and surveillance applications. Whereas it used to be the privilege of border patrols and other government related agencies to use a thermal imaging camera, today more and more industrial facilities as well as residential owners are using the power of thermal imaging to protect their valuable assets against theft, vandalism or - even worse - terrorist attacks. Thermal imaging is also used by the police and other law enforcement agencies to find and follow suspects in total darkness.

Search and Rescue Missions
The main task of Search and Rescue professionals is to find people which are in distress, lost, sick or injured. Either in a remote or difficult to access area, such as mountains, desert or forest, or at sea, whether close to shore or not. Thermal imaging cameras are sometimes mounted on helicopters flying over the scene to be searched. A thermal imager seamlessly detects human activity in otherwise remote areas so that the victim can be found before it is too late. A thermal imaging camera can do this in the darkest of nights, on land, in the air or at sea.

Building Inspections
Today, we have become increasingly conscious of energy consumption. Global warming is also known to be largely caused by pollution related to burning fossil fuels used for heating buildings. Therefore, more and more countries are setting up legislation to inspect buildings on a regular basis for heat losses. A thermal imaging camera is an easy-to-use tool for making insulation defects and other building anomalies visible. It is probably just a matter of time before every building will be inspected with a thermal imaging camera.

Optical Gas Imaging
Many companies are specialized in transporting and transforming industrial gases and chemical compounds. Yet, most of these ingredients are invisible to the naked eye. Not for thermal gas imaging cameras, which offer a number of benefits compared to traditional "sniffers": they scan a broader area much more rapidly and in areas that are difficult to reach with contact measurement tools. Infrared displays a leak as a plume of vapor in the infrared image. Thanks to early leak detection, severe damage or even the loss of human lives can be avoided.

Traffic Monitoring
One of the latest evolutions is the use of thermal imaging for traffic monitoring. Traffic managers all over the world are starting to use thermal imaging cameras to monitor and manage traffic streams. Be it for monitoring motorists and pedestrians in urban areas, for detecting incidents on highways and in tunnels, or for traffic data collection purposes, thermal traffic camera systems can enhance traffic safety and mobility.

The Future of Thermal Imaging
Undoubtedly, thermal imaging cameras will follow the same path as other products followed before. The equipment will become more compact, image quality will further improve and more features will be implemented into thermal cameras.
As an example of the ongoing miniaturization of thermal imaging cores, Flir introduced its Lepton core in January 2014. Lepton is an advanced longwave infrared (LWIR) imager that is 10 times less expensive than conventional IR cameras (fig. 7). It is a complete IR camera solution and provides a resolution of 80 × 60 active pixels. The Flir Lepton is ultra- compact and can be easily fitted inside a cell phone. It brings thermal imaging to a new generation of electronic instruments for work, play and mission-critical applications.
The introduction of the Flir Lepton coincided with the launch of the Flir One, the first consumer-oriented thermal imaging system. Flir One places the power of thermal imaging technology into the palm of the consumer via an easy-to-use smartphone accessory case (fig. 8). The personal imager represented a dramatic step in Flir’s pursuit of 'infrared everywhere’.
Followed by the Lepton launch, Flir Systems continued to find new and innovative uses for its increasingly more affordable thermal imaging technologies. In September 2014, Flir launched the AX8 automation sensor, a Lepton-enabled thermal sensor for early detection of temperature-related issues in electrical and mechanical equipment. For the building and industrial sector, Flir launched the C2, the world's first full-featured, pocket-sized thermal camera designed for a wide range of building and electrical/mechanical applications.
As thermal imaging cameras are finding their way in more and more consumer oriented applications like driver vision enhancement and home security, the interest for the product will rise, production volumes will go up and prices will come down. It’s hard to tell where this trend will lead. But it’s safe to say that in the coming years, thermal imaging will become more accessible to an even bigger professional and consumer oriented audience.