Thermography is the visualization and measurement of the thermal energy emitted by an object using a camera

Thermal, or infrared, energy is light with a wavelength too long to be seen by the human eye. This energy is that portion of the electromagnetic spectrum that we perceive as heat. Unlike visible light, in the infrared world, any object above absolute zero emits heat. Therefore, even from very cold objects such as eg B. ice cubes from infrared radiation. The higher the temperature of an object, the more intense the infrared radiation it emits. In the infrared we can see things that are otherwise invisible to our eyes.

Infrared cameras generate images of the invisible infrared or heat radiation and thus enable precise non-contact temperature measurements. Almost every technical component gets hot before it fails. Infrared cameras show these problems early, making them an extremely cost-effective and valuable tool that can be used in a wide variety of applications. In view of the fact that companies are now striving to make their production processes more efficient, reduce energy consumption, improve product quality and increase safety in the workplace, new applications for infrared systems are constantly emerging.
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 You can find more information on the  Flir company website

Here are some pictures from practice