| Laser Raman water temperature measurement technology can rapidly measure the temperature of seawater at different depths in a large area of water.It has incomparable advantages over traditional contact measurement and microwave remote sensing,and is of great significance to climate monitoring,military and other fields.However,the existing laser Raman water temperature measuring system has the disadvantages of complex system structure,slow measuring speed and high cost.With the shift of detection range to many fields such as deep-sea and deep space in-situ detection and real-time security inspection,it is more and more meaningful to develop a low-cost,miniaturized and strong detection ability Raman water temperature measurement system.To solve the above problems,a dispersion-type miniaturized Raman spectral water temperature measurement system was developed by using the portable Raman spectrometer independently developed by the Research Institute.Then,according to the results of Raman spectrum analysis,the design scheme of spectroscopic Raman temperature measuring system was determined,and the software and hardware system was developed.The preliminary experimental research of near and remote temperature measuring was carried out,and the experimental results were compared with those of dispersive miniaturized Raman temperature measuring system.Firstly,the basic principle of water temperature measurement by Raman spectroscopy is studied,and the data processing method,spectral characteristics and modeling method of water temperature are analyzed.On this basis,a dispersive miniaturized Raman water temperature measurement system is built by using a CMOS based portable Raman spectrometer developed by the Institute,and a spectrum real-time acquisition and data processing system based on Lab VIEW is developed.The detection sensitivity and signal-to-noise ratio are effectively improved by using time-space accumulation,background subtraction,normalization,wave number calibration and other preprocessing methods.Secondly,the Raman spectra of different temperature water are measured by the dispersion miniaturized Raman spectrum water temperature measurement system.The Raman spectrum characteristics are extracted by origin,and the spectral characteristics water temperature modeling is carried out.The measurement accuracy of the two modeling methods is compared and analyzed,and the parameters of the real-time water temperature inversion module are determined.In the further real-time measurement of water temperature,it is found that the Raman spectrum measured by the system has the problem of lateral drift,which leads to the overall drift of temperature measurement results at different times.In order to solve this problem,a threshold area ratio method is proposed,which is proved to be effective by experimental research,and the non-contact real-time and high-precision measurement of water temperature in situ is realized.Finally,according to the above-mentioned measured Raman spectrum data,the influence of the center position and range of the temperature sensitive band on the measurement accuracy is studied,and the parameters of the narrow-band filter in the high and low frequency band of the spectroscopic Raman water temperature measurement system are determined.The spectroscopic Raman water temperature measurement system is developed by using the high-sensitivity photomultiplier tube,and the real-time data acquisition and processing system is developed The temperature of water at different distance was measured experimentally,and compared with the dispersive miniaturized Raman water temperature measurement system in terms of measurement mode,measurement speed,measurement distance and measurement accuracy. |
