[Research on high-precision temperature measurement system based on near infrared spectroscopy]

At present, the interference from outside radiation under the complex environment is difficult to eliminate by using the infrared thermometry method. It leads to the low measurement accuracy. In the present paper, a high-precision infrared temperature measurement system was designed. The light filter method is presented in this system. The broadband filters and three-level interference filter were combined in this method. According to the method, the near-infrared spectra sent out by high temperature object is filtered. The high temperature background light and the environment obtrusive light are filtered out. In this way, two monochromatic spectra are obtained. The radiation power ratio is received after receiving by the infrared detector. Then the temperature is obtained by calculating. In this system, the bandwidth of monochromatic spectrum permeated is only 1 nm. The inhibition of radiation from background light and ambient light except transmittance spectrum is up to 8 orders of magnitude. The measurement error caused by the ambient temperature heating of the measured object is reduced. The accuracy of the temperature measurement system is improved. Finally, the temperature measurement system is feasible according to the experiment result. The precision reached to 0.2%.