Any object in nature whose temperature is higher than absolute zero (-273. 15℃) can radiate infrared energy. The principle of infrared thermal imaging is based on the temperature difference between the detected object and the background, and its core technology is the production and development of infrared focal plane detector.

The infrared detector can detect and collect the infrared energy of the target object, convert the infrared thermal radiation on the surface of the object into corresponding electrical signals, and then form a video image observed by the naked eye after amplification and video processing. Generally speaking, invisible infrared radiation is turned into visible thermal image, which can reflect the temperature distribution of the target surface.

Because thermal imaging is based on detecting the temperature difference between the target and the background, thermal imaging can be seen as long as there is a temperature difference between the temperature of people and the temperature of reeds.