Research On Temperature Measurement Technology And Application Based On Infrared Thermal Imager

As one of the high technologies which are developing rapidly in the present, the infrared imaging temperature measurement has been extensively used in the military, paramilitary and civil areas and it is playing an irreplaceable role. The developed countries, such as the US, Germany, UK and France, lay much store by the research and appliance of the technology for the infrared imaging temperature measurement. To master the development, appliance and trends of the thermal imaging temperature measurement technology is helpful in enlightening scientific thinking and providing guidance for the improvement of thermal imager.This paper presents a study of the technology for accurate temperature measurement with infrared thermal imager and its applicance with the principle of the infrared thermal imaging temperature measurement. It also treats the thermal conductivity of carbon fiber fabric and the comfortableness of clothing materials with the infrared thermal imager. In brief, the main researches in the modeling of thermal imaging temperature and measurement technology in this paper are as follows:(1) According to the heat radiation theory and the principle of the infrared thermal imaging temperature measurement, the factors influencing the infrared thermal imaging temperature measurement are systematically analyzed and the influences of the measured object's surface radiativity, absorptivity, atmospheric transmissivity, ambient temperature and atmosphere temperature on the error of temperature measurement are identified. A physical model of infrared thermal imaging temperature measurement is built.(2) The calibration curves under different accuracies and measurement conditions are acquired with the radiation and reflection of infrared rays on the object surface and with the physical process of the infrared rays'transmission in the atmosphere. BP neural network calculation is designed for fitting of characteristic curve of gray and temperature in the experiment of temperature calibration to ensure the accurate measurement of temperature with infrared thermal imager.(3) A study is presented of the emissivity, reflectivity and transmissivity of the measured object and then the effective radiation of the object surface is achieved with the three major laws of the infrared physics. The equation for temperature measurement by radiation is formulated and the model of the transformation from target temperature fields to equivalent temperature fields is constructed. The paper puts forward the method of accurate temperature measurement in field with infrared thermal imager and makes the second calibration of atmospheric transmission coefficient. The measured temperature of the unknown radiation object with the second atmospheric transmission coefficient is calibrated and the accurate measurement of the radiation temperature of the unknown radiation object is determined.(4) A platform for testing the thermal conductivity of carbon fiber is constructed based on infrared thermal imaging technology. The analysis and measurement of the temperature fields of carbon fiber fabric are carried out with the infrared thermal imaging technology. The difference of thermal conductivity of the carbon fiber fabric treated at different temperatures is analyzed with the changing patterns of temperature versus time. Consequently a new method, which proves an effective one, is presented for analyzing and evaluating the thermal conductivity of this kind of material.(5) A platform for testing clothing comfortableness is built based on the infrared imaging technology to carry out the experimental measurement of the clothing temperature in set circumstances. An infrared thermal imager is used to directly measure the distribution of the temperature fields of the clothing surface in different circumstances when the clothing is worn, judge the change of the actual temperature in that event and then deduce the thermal insulation properties of the clothing and the cloth. The thermal resistance values of cloth are compared by the highest temperature of the cloth clinging to skin and in turn the relative values of thermal insulation of the clothing are judged.The accurate temperature measurement with infrared thermal imager model is build and the firm theoretical and technical base on is set up too in this paper.