The Design And Improvement Of Colorimetric Temperature Measurement

Temperature measurement is very important in fields of scientific research,industrial production,military application and so on.Nowadays,infrared thermometer has gradually replaced contact thermometer because of its merits such as not disturbing thermal field and quick response.With the development of infrared detection technology,infrared thermometer is becoming more and more accurate and applicable.Among different infrared temperature measurement methods,colorimetric temperature measurement method has gradually occupied an important position for its large measuring range,high accuracy and strong anti-interface capacity.Compared to foreign research,domestic research on infrared thermometer still lacks accuracy and anti-interface capacity.This paper focuses on ways to improve accuracy of colorimetric temperature measurement method.Based on the theoretical basis of traditional colorimetric temperature measurement method,analyzes the effect of filter bandwidth on accuracy.Based on the traditional calibration method,studies function relations between emissivity,temperature and wavelength,thus calibration method is improved.In addition,focuses on the influence of slope and background temperature on accuracy of temperature measurement and brings forward compensation measures.The main content is to design colorimetric temperature measurement instrument.In the design of the whole system,according to demand analysis,puts forward general design scheme and corresponding optical,hardware and software design.In optical design,chooses double channel,non-modulated optical system and InGaAs photoelectric detector.To weaken atmospheric attenuation effect,wavelength of two channels iscarefully chosen and ultimately determines the dual band 1.2?m and1.55?m.In hardware design,in order to improve the accuracy of temperature measurement,carefully analyzes the effects of temperature drift characteristics and noise in chip selection and circuit design.Signal processing circuit of the system mainly includes I-V converter,low pass filter,50 Hz notch filter and A/D conversion circuit.Other parts,such as human-computer interaction,communication and ambient temperature acquisition modules are also designed.In software design,codes are all written with C language in embedded processor and PC upper processor.Moreover,discusses the accuracy of least square fitting and spline curve fitting.Finally,the designed thermometer is calibrated with standard radiation source and its uncertainty and repeatability are analyzed through experiments.Results show that in the range of this system(500~1200?),its accuracy is within 0.5% while repeatability is within 0.1%,which are both within expectation.Besides,the paper analyzes major error sources of this system and puts forward corresponding solutions to reduce error.