Principle of dual band combiner technology

dual band combiner

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dual band combiner converts infrared radiation emitted by an object (such as molten steel) into electrical signals. The infrared radiation energy corresponds to the temperature of the object (such as molten steel). Based on the converted electrical signals, the temperature of the object (such as molten steel) can be determined.

Modern development

Infrared thermometry technology has been developed to scan the temperature of the surface with thermal changes, determine the temperature distribution image, quickly detect the hidden temperature difference, this is the infrared thermal imager. Infrared thermal imager was first used in **, the United States TI company 19 years developed the world's first infrared scanning reconnaissance system. Since then, infrared thermal imaging technology has been applied to aircraft, tanks, warships and other weapons in western countries. As a thermal sight system for reconnaissance targets, it has greatly improved the ability to search and hit targets. However, how to make the infrared temperature measurement technology be widely used is still an application topic worth studying at present.

Working principle of the dual band combiner

The dual band combiner consists of an optical system, a photodetector, a signal amplifier, signal processing, and display output. The optical system gathers the target infrared radiation energy in its field of view. The size of the field of view is determined by the optical parts of the thermometer and their positions. 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 algorithm of the instrument internal therapy and the target emissivity.

In nature, all objects with temperatures above ** zero are constantly radiating infrared energy into the surrounding space. The amount of infrared radiation energy of an object and its distribution by wavelength have a very close relationship with its surface temperature. Therefore, by measuring the infrared energy radiated by the object itself, it can accurately measure its surface temperature, which is the objective basis of infrared radiation temperature measurement.

A black body is an idealized radiator that absorbs all wavelengths of radiant energy, has no reflection or penetration of energy, and has an emissivity of 1 on its surface. However, almost all actual objects in nature are not black bodies. In order to clarify and obtain the distribution law of infrared radiation, appropriate models must be selected in theoretical research, which is the quantized oscillator model of body cavity radiation proposed by Planck. Thus, Planck's law of blackbody radiation is derived, namely, the spectral radiance of blackbody expressed by wavelength. This is the starting point of all infrared radiation theory, so called blackbody radiation law. In addition to the radiation wavelength and the temperature of the object, the radiation amount of all actual objects is also related to the material type, preparation method, thermal process, surface state and environmental conditions. Therefore, in order for the blackbody radiation law to apply to all practical objects, a proportional coefficient related to the properties of the material and the state of the surface must be introduced, that is, the emissivity. This coefficient indicates how close the actual object's thermal radiation is to the blackbody radiation, with a value between zero and a value less than 1. According to the radiation law, as long as you know the emissivity of the material, you know the infrared radiation characteristics of any object. The main factors affecting the emissivity of yarn are material type, surface roughness, physical and chemical structure and material thickness.

When the infrared radiation thermometer is used to measure the temperature of the target, it is necessary to measure the infrared radiation of the target in its band range, and then the temperature of the target is calculated by the thermometer. The monochromatic thermometer is proportional to the radiation in the band; The two-color thermometer is proportional to the ratio of radiation in the two bands.

dual band combiner