The Study About The Effect Of The Distance And The Angle Of Vision On The Precision Of Temperature Measurement Using Infrared Thermal Imaging System

The infrared thermal imaging system has been a hot issue in the field of high temperature measurement for low cost, quick response and information concerning temperature field. But, light-path system of the current infrared thermal imaging system is hard to receive the temperature field images of various wavelengths, so it cannot realize multi-wavelength temperature measurement and colorimetric temperature measurement. Therefore, the object emission rate and true temperature cannot be measured at same time and the anti-interference ability is very poor. In addition, the accuracy of the current array thermometers is low because they aren’t compensated the errors caused by target distance and angular field at the actual installation and calibration.For the issues mentioned above, the thesis establishes an optical system of the near-infrared array CCD thermometer that is able to receive multiplex signals, and build a compensation model for a better accuracy of measurement which is influenced by target distance and angular field. First of all, the thesis, which’s based on the principle of infrared radiation, analyzes the components of the optical system of a near-infrared array CCD thermometer by employing Flange Spectrophotometry, and conducts model selection of devices of each part. Then, based on the Geometrical Optics and the Infrared Radiation Temperature Measurement Theory, the thesis analyzes effects of target distance and angular field on thermometry, and deduces the relation between errors of temperature measurement and target distance and angular field, and thus compensates the errors caused in the measurement. Finally, the established platform for optical experiments proves the compensation model. By calculating the compensated errors, accuracy of the model is confirmed.By the author’s analysis and utilization of the temperature measuring system consisted of Flange and a near-infrared array CCD thermometer, the target of receiving multiplex signals is achieved in a short time; When conducting an experiment on objects, of which color temperature is around1160K, the compensation model for target distance can fix the absolution of the temperature’s comparative error in0.10%at the object distances of0.5m-2.5m; When conducting an experiment on objects, of which color temperature is around1293K, the compensation model for angular field can fix the absolution of the temperature’s comparative error in0.05%if the measuring scope is between0°nd5°; while the absolution of the temperature’s comparative error can be fixed in0.82%if the measuring scope is between0°nd15when conducting an experiment on objects, of which color temperature is around1162K.