In nature, all objects whose temperature is higher than absolute zero are constantly sending out infrared radiation energy to the surrounding space. The infrared radiation energy of an object and its distribution by wavelength are closely related to its surface temperature. Therefore, through the measurement of the infrared energy of the object itself, the surface temperature of the object can be accurately measured, which is the objective basis of the infrared radiation temperature measurement.
The infrared thermometer is composed of optical system, photoelectric detector, signal amplifier, signal processing and display output. The optical system gathers the infrared radiation energy of the target in its field of view. The size of the field of view is determined by the optical parts of the thermometer and its position. The infrared energy is focused on the photodetectors and converted into corresponding electrical signals. After the amplifier and signal processing circuit, the signal is converted into the temperature value of the measured target after being corrected according to the algorithm of instrument internal therapy and target emissivity. In addition, the influence of the target and the environmental conditions of the thermometer, such as temperature, atmosphere, pollution and interference, on the performance index and the correction method should be considered.