Infrared radiation is one of the most extensive electromagnetic radiation in nature. It is based on the fact that any object will produce its own molecules and atoms with irregular movement under normal environment, and continuously radiate thermal infrared energy. The more intense the movement of molecules and atoms, the greater the radiation energy, and vice versa.

An object whose temperature is above absolute zero will radiate infrared rays due to its own molecular motion. After the power signal radiated by the object is converted into an electrical signal by the infrared detector, the output signal of the imaging device can completely simulate the spatial distribution of the surface temperature of the scanned object one-to-one, and transmit it to the display screen after being processed by the electronic system to obtain a thermal image corresponding to the surface thermal distribution of the object.