What is infrared temperature measurement?
What is infrared temperature measurement?
In the field of measurement, "temperature" is the most commonly used physical parameter after "time". Based on the principle of Planck and Boltzmann's radiation law, the infrared temperature sensor measures the temperature of the measured object by absorbing infrared radiation. So, how is non-contact temperature measurement achieved?
Any object whose temperature is higher than absolute zero (0 K or -273.15°C) will emit electromagnetic radiation from the surface, and the radiation is proportional to the inherent temperature of the object. In this kind of radiation, infrared radiation used for temperature measurement is included. After the radiation penetrates the atmosphere, it can be concentrated on the detector with the help of a special lens. Subsequently, the detector generates an electrical signal proportional to the radiation. The signal is amplified and converted into an output signal proportional to the temperature of the object by receiving continuous digital signal processing. In this way, the temperature measurement value will be displayed on the display, or output as a signal.
When using radiation to measure temperature, the emissivity ε (Epsilon) plays a vital role. It shows the relationship between the radiation value of the actual object and the black body. The emissivity of a black body is 1 (maximum). However, there are not many objects that can satisfy the ideal condition of blackbody. When calibrating the sensor, the contact surface of the radiator (including the recommended wavelength: 0.99) is generally used.
In terms of its wavelength, many objects usually have a constant emissivity, but their radiation ability is far inferior to black bodies. They are called gray bodies. If the emissivity of an object depends on its temperature and wavelength (such as metals), such objects are called selective radiators. In both cases, the missing radiation part is supplemented by the emissivity clarification. When using a selective radiator, you need to keep in mind the measured wavelength (for metal, select shortwave).
In addition to the radiation emitted from the surface of the object, the infrared temperature sensor can also receive the reflected radiation from the surrounding environment, and perhaps the penetrating infrared radiation of the measured object.
∷
