Everyone has seen pictures or videos taken by a thermal imaging camera. These recordings show a different picture of reality, one that cannot be seen with the naked eye. But what technology is actually behind such a thermal imaging camera and what is this technology usually used for?
To understand exactly how a thermal imaging camera works, one must first study thermography. This is an imaging process that uses infrared radiation to interpret the surface temperature of living beings and objects.
This technology is based on a camera that can capture a light spectrum that would not be visible to the human eye without technical aids. In the case of a thermal imaging camera, this is infrared radiation, which is also referred to as thermal radiation for a reason. The wave range of infrared radiation extends from 780 nanometers to one millimeter and is thus directly above the wave range that the human eye can perceive as visible light (between 400 and 780 nanometers).
An object radiates according to its temperature within the infrared range in a very specific wavelength. Temperature differences mean different wavelengths of thermal radiation. A thermal imaging camera captures precisely these differences in the wavelengths and then makes them visible. The greater the temperature differences, the easier it is to recognize objects or living beings. Some thermal imaging cameras have a scale on which the approximate temperature can be read from the color.
Where are thermal imaging cameras used everywhere?
Thermal imaging cameras are used more often than you might think at first glance. Based on the numerous areas of application, it quickly becomes clear how flexible thermography is and how important and natural this technology has already become in many people’s everyday lives. Some examples of the use of thermal imaging cameras are:
Fire detection or fire fighting
Special thermal imaging cameras help the fire brigade with fire detection (e.g. in large forest areas) and with fire fighting, where they can reliably detect even the smallest fires.
Thermal imaging cameras are also increasingly being mounted on government drones. These help with aerial reconnaissance in areas that are difficult to access or also with the pursuit of suspects. On the other hand, such heat-sensitive special cameras are rarely found on private hobby drones.
Research and science
In research and science, experts also rely on thermal imaging cameras. In research, for example, they show the movement patterns of animals or can be used to monitor the environment; in science, thermal imaging cameras can be components of experiments or can be used to search for sources of error.
Nature observation / hobby photography
Thermal imaging cameras are also used in nature observation and in hobby photography – albeit very rarely. To do this, they show the viewer images that he could never see without modern technology.
Thermography is also used in shipping for additional collision detection. Thermal imaging cameras can protect against collisions with other ships or objects in the water, especially when visibility is poor at night or due to rain, snow or fog. Port entrances may also be easier to find using thermal images. Nevertheless, it should be mentioned that thermography often reaches its limits at sea.
Thermal imaging cameras are used for professional building and property protection and increasingly also for private security systems. The advantage over conventional night vision cameras is that contrasts can be seen much better with thermography.
Attachments or external hand tools for hunting
Although devices for sighting with thermal imaging optics are prohibited under the Federal Hunting Act, thermal imaging cameras such as the Helion series from Pulsar may be used for observation purposes. The federal states are also free to “expand or restrict this regulation for special reasons” (Section 19 (2) BJagdG).
Thermal imaging cameras in industry
Many thermal imaging cameras are used for industrial purposes, the areas of application being very different. The latest generation of heat-sensitive special cameras can help, for example, with monitoring explosive gases, or they can make poorly lit areas safer (for example in mining).
Thermal imaging cameras with ever better thermal sensitivity
A thermal imaging camera shows different wavelengths of radiation and then interprets the temperature. However, if an object is to be filmed that has almost the same temperature as the background environment, previous thermal imaging cameras quickly reach their limits. For this reason, thermography is also constantly being improved and optimized. The most modern thermal imaging cameras convince with an extremely high level of detail recognition – even with the lowest thermal contrasts.
Thermal imaging cameras are also getting better and better in terms of range. Good cameras of this kind can, for example, make a small bush fire visible at a distance of several kilometers in the dark and even small, handy devices of the latest generation are able to easily locate objects one to two kilometers away in absolute darkness.
Researchers are already working on the new generation of thermal imaging cameras. These could then, for example, make shipping, where the technology is currently still reaching its limits, reliably and safer.