The influence of thermometer object emissivity on radiation temperature measurement:
Almost all actual objects that exist in nature are not black bodies. The radiation amount of all actual objects depends not only on the radiation wavelength and the temperature of the object, but also on factors such as the type of material, preparation method, thermal process, surface state and environmental conditions of the object. Therefore, in order to make the black body radiation law applicable to all real objects, a proportional coefficient related to the material properties and surface state must be introduced, that is, the emissivity. This coefficient represents how close the thermal radiation of an actual object is to blackbody radiation, and its value is between zero and a value less than 1. According to the radiation law, as long as you know the emissivity of the material, you can know the infrared radiation characteristics of any object.
The main factors that affect the emissivity of infrared thermometers are:
Material type, surface roughness, physical and chemical structure and material thickness, etc.
When using an infrared radiation thermometer to measure the temperature of a target, the amount of infrared radiation of the target within its band range must first be measured, and then the temperature of the measured target is calculated by the thermometer. A single-color thermometer is proportional to the amount of radiation within the band: a two-color thermometer is proportional to the ratio of the amount of radiation in the two bands.
The infrared thermometer must correctly select the infrared system:
Infrared thermometer consists of optical system, photoelectric detector, signal amplifier, signal processing, display output and other parts. The optical system gathers the target infrared radiation energy within its field of view, and 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 photodetector and converted into a corresponding electrical signal. The signal passes through the amplifier and signal processing circuit, and is converted into the temperature value of the measured target after correction according to the internal treatment algorithm of the instrument and the target emissivity.
