Also known as infrared thermography, thermal imaging is a technique that is used in the detection of radiation, mostly in the form of heat, and converting the radiation into an image. Because thermal imaging techniques allow us to see “images” or radiation that are invisible to the naked eye, they find wide applications in various kinds of human endeavors.
Thermal imaging is as close as you can get to “seeing through walls” and it is therefore deployed in numerous applications such as security surveillance systems to detect or track intruders, firefighting, search and rescue operations, maritime navigation applications, gas detection, equipment preventive maintenance, termite or pest detection, electrical troubleshooting, leak detection, building maintenance and numerous other uses. Thermal imaging techniques find wide applications in diagnostic work in all kinds of industries.
The principle of Thermal Imaging Techniques
Thermal imaging works on the principle that all objects emit infrared signals at different frequencies, based on their temperature. The technology deploys sophisticated infrared cameras that pick up the infrared heat emitted by objects and scan them to produce temperature patterns called thermogram. The thermogram is translated into electric impulses and subsequently, thermal images of the object.
The thermal imaging cameras used are temperature-calibrated and are generally able to accurately measure and map out infrared signals into data for display. Once processed by the camera’s signal processing unit, the infrared signals emitted by an object will appear in the form of numerous colors with the variation in the colors representing the variation of the intensity of the infrared radiation that was emitted by the object. The combination of all the infrared impulses will create a discernible image that can be interpreted easily by humans. In a thermal image, the object on which the camera is focused will appear brightest while the surrounding objects that are not emitting any infrared signals appear dark.
History of Thermal Imaging
Like most of the important modern inventions, thermography was invented during the cold war and was deployed in top-secret spying operations on military installations. After it was discovered that some cancers emitted heat, thermal imaging was also deployed in medical diagnostics in the 1950s.
Today, thanks to its accuracy, thermal imaging is used widely in a plethora of industries beyond the military applications. In the military, it is mostly deployed in the night vision equipment.
However, the most widespread applications have been outside the military. They are used as diagnostic tools in large industrial enterprises where they make valuable companions for predictive maintenance operations.
Because thermal imaging allows for “vision in darkness”, they are also used widely in the security and surveillance industry. Unlike normal security cameras that require light to capture useful information, thermal imaging cameras are able to capture much more even in pitch darkness. Thermal imaging cameras can tell whether someone is stressed or sick and they can even detect hidden weapons such as knives and guns.
In the construction industry, the thermal imaging techniques can be used to identify faults that are not visible to the naked eye. As research into the thermal imaging techniques continue, human beings will in the future be equipped with the capability to get even clearer and more refined images of their surroundings beyond what is discernible with the normal cameras or even the naked eye.