光纤测温系统信号处理方法的研究与实现
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摘要
随着对光纤与光纤器件研究的深入,作为检测器件的光纤传感器也越来越受到人们的重视。近一段时期,光纤传感技术得到了迅速的发展,目前已在科学研究与工程应用领域得到了广泛的应用。分布式光纤温度传感器作为光纤传感器的一个重要分支,也随着其技术的不断成熟渐渐的在各种工程当中得到了应用。
分布式光纤测温系统的信号采集和数据后处理是系统的核心部分。该部分的检测精度和速度决定了整个系统的测量精度,空间分辨率,采集速度以及最后的请求响应时间。如何提高系统各个部分的处理速度,协调好数据传输,成为设计分布式光纤测温系统的关键。
论文深入的分析了分布式光纤测温系统的测温原理,并对系统光路、高速采集电路和软件滤波部分提出了改进方案。通过对系统各部分的改进,提高了分布式光纤测温系统的响应时间和测量精度等性能指标。
论文详细介绍了分布式光纤测温系统的系统光路部分、高速A/D采集电路部分和软件设计部分的信号处理方法。在系统光路设计部分通过计算给出了光纤耦合器的最佳分光比,使系统光路部分的信号信噪比得到提高。在高速A/D采集电路部分,本文设计了高速缓存机制可以有效的将采集到的数据输出到DSP中进行数据处理。在软件设计部分,针对分布式光纤测温系统测量周期过长的问题,在保证系统的时间分辨率和空间分辨率的前提下,本文提出了一种自适应阈值小波滤波算法。该算法能够通过训练信号来确定各尺度下的非线性阈值函数参数,然后采用阈值自适应的小波滤波进行温度信号滤波。实验证明,该算法能够在有效缩短温度测量周期的同时提高系统的精确性。
With the deep research on optical fiber and optical fiber devices, the optical fiber sensor that is used to test devices has gained more and more attention from people. Recently, the optical fiber sensing technology gets rapid development and has been used widely in the scientific research and engineering application field. The distributed optical fiber temperature sensor , as an important branch of optical fiber sensor,distributed optical fiber temperature sensor has been gradually used in all kinds of projects as its technology becomes mutual.
The most important part of distribute fiber temperature-measured system are signal collecting, data processing and background software programming. They decide the collecting precision, collecting speed and final response time. How to improve the processing speed and how to coordinate data transmission between different parts are most important in this system.
This thesis deeply analyzes the temperature-measuring principle of distributed optical fiber and poses the reform plan for the optical path of system,high speed acquisition circuit and software filter.Through the improvement of each part of the system,it improves the response time and measuring accuracy and so many other performance indexes of the temperature-measuring system of distributed optical fiber.
This thesis detailedly introduces the signal processing method of the optical path of system part,high speed acquisition circuit part and software design part of temperature-measuring system of distributed optical fiber. This thesis gives the best splitting ratio of the fiber coupler and makes signal-to-noise ratio of the optical path of system part higher.It designs a high speed cache which can input the data into the DSP to process.In the part of software design, the system usually demands a long measuring period, while guarantee time and space resolution of the system, a method called adaptive threshold filter based on wavelet was proposed in this paper.This parameters of the non-line threshold filtering function in different wavelet scales is based on training signals,then using the adaptive threshold filtering wavelet method to de-noising the temperature signal. The experiments indicate that the measuring period is greatly reduced, and the system becomes more precise.
分布式光纤测温系统的信号采集和数据后处理是系统的核心部分。该部分的检测精度和速度决定了整个系统的测量精度,空间分辨率,采集速度以及最后的请求响应时间。如何提高系统各个部分的处理速度,协调好数据传输,成为设计分布式光纤测温系统的关键。
论文深入的分析了分布式光纤测温系统的测温原理,并对系统光路、高速采集电路和软件滤波部分提出了改进方案。通过对系统各部分的改进,提高了分布式光纤测温系统的响应时间和测量精度等性能指标。
论文详细介绍了分布式光纤测温系统的系统光路部分、高速A/D采集电路部分和软件设计部分的信号处理方法。在系统光路设计部分通过计算给出了光纤耦合器的最佳分光比,使系统光路部分的信号信噪比得到提高。在高速A/D采集电路部分,本文设计了高速缓存机制可以有效的将采集到的数据输出到DSP中进行数据处理。在软件设计部分,针对分布式光纤测温系统测量周期过长的问题,在保证系统的时间分辨率和空间分辨率的前提下,本文提出了一种自适应阈值小波滤波算法。该算法能够通过训练信号来确定各尺度下的非线性阈值函数参数,然后采用阈值自适应的小波滤波进行温度信号滤波。实验证明,该算法能够在有效缩短温度测量周期的同时提高系统的精确性。
With the deep research on optical fiber and optical fiber devices, the optical fiber sensor that is used to test devices has gained more and more attention from people. Recently, the optical fiber sensing technology gets rapid development and has been used widely in the scientific research and engineering application field. The distributed optical fiber temperature sensor , as an important branch of optical fiber sensor,distributed optical fiber temperature sensor has been gradually used in all kinds of projects as its technology becomes mutual.
The most important part of distribute fiber temperature-measured system are signal collecting, data processing and background software programming. They decide the collecting precision, collecting speed and final response time. How to improve the processing speed and how to coordinate data transmission between different parts are most important in this system.
This thesis deeply analyzes the temperature-measuring principle of distributed optical fiber and poses the reform plan for the optical path of system,high speed acquisition circuit and software filter.Through the improvement of each part of the system,it improves the response time and measuring accuracy and so many other performance indexes of the temperature-measuring system of distributed optical fiber.
This thesis detailedly introduces the signal processing method of the optical path of system part,high speed acquisition circuit part and software design part of temperature-measuring system of distributed optical fiber. This thesis gives the best splitting ratio of the fiber coupler and makes signal-to-noise ratio of the optical path of system part higher.It designs a high speed cache which can input the data into the DSP to process.In the part of software design, the system usually demands a long measuring period, while guarantee time and space resolution of the system, a method called adaptive threshold filter based on wavelet was proposed in this paper.This parameters of the non-line threshold filtering function in different wavelet scales is based on training signals,then using the adaptive threshold filtering wavelet method to de-noising the temperature signal. The experiments indicate that the measuring period is greatly reduced, and the system becomes more precise.
引文
[1]Culshaw B,Darkin J.光纤传感器.李少慧,宁雅农,李志高译.武汉:华中理工大学出版社,1997:583-605.
[2]Hartog A H.Distributed temperature sensor based on liquid core optical fiber.IEEE Lightwave Tech,1983,1(3):498-509.
[3]Hartog A H.Distributed temperature sensor in solid core fibers.Electron Lett,1985,21(4):1061.
[4]Horiguchi T.Tensile strain dependence of brillouin frequency shift in silica optical fibers.IEEE Photon.Tech Lett,1989,1(5):107-108.
[5]Culverhouse D.Potential of stimulated brillouin scattering as sensing mechanism for distributed temperature sensors.Tech Lett,1989,25(14):913-915.
[6]Kurshima T,Horiguchi T.Brillouin optical fiber time domain reflectometry.ICICE Trans Commun,1993,76(4):718-721.
[7]Newson T P,Kee H.All-fiber system for simultaneous interrogation of distributed strain and temperature sensing by spontaneous brillouin scattering.Optical Lett,2000,25(10):620-626.
[8]Bao X.Experimental and theoretical studies on a distributed temperature sensor based on brillouin scattering.Lightwave Tech,1995,13(7):55-60.
[9]Dakin J P,Pratt D J.Distributed optical fiber sensors.SPIE,1985,17(9):76-108.
[10]周胜军,刘凤军.分布式光纤温度传感器的原理和应用.半导体光电,1998,19(5):287-290.
[11]黄尚廉,梁大巍.分布式光纤温度传感器系统的研究.仪器仪表学报,1991,12(4):359-364.
[12]张在宣,刘天夫.激光拉曼型分布式光纤温度传感器系统.光学学报,1995,16(11):1585-1589.
[13]张艺,张在宣,金仁诛.远程分布式光纤传感器系统的设计和制造.光电工程,2005,32(4):45-48.
[14]Kersey A D.Fiber grating sensors.Journal of lightwave technology,1997,15(8):1442-1463.
[15]Rao Y J,Jackson D A.A prototype multiplexing system for use with a large number of fiber-optic-based extrinsic Fabry-Perot sensors exploiting low coherence interrogation.SPIE,1995,25(7):90-98.
[16]Ifeachor E C,Jervis B W.Dgital signal processing:a practical approach.USA:Addison Wesley publishing company,1993.
[17]Chan C CShi C Z,Gong J M et al.Enhancement of the measurement range of FBG sensors in a WDM network using a minimum variance shift technique coupled with amplitude-wavelength dual coding.Optics Communications,2003,215(4):289-294.
[18]张岩红.分布式光纤温度传感器信号处理系统的研究与设计:(硕士学位论文).河北省秦皇岛市:燕山大学,2003.
[19]程光煦.拉曼布里渊散射.北京:科学出版社,2001.
[20]史晓锋,李铮,蔡志权.分布式光纤测温系统及其测温精度分析.测控技术,2002,21(1):9-10.
[21]Lees G P.Advances in optical fiber distributed temperaturesensing using the Landau Placzek ratio.IEEE Photonics Technol,1998,10(1):126-128.
[23]倪玉婷,吕辰刚,葛春风,等.基于OTDR的分布式光纤传感器的原理及其应用.光纤与电缆及其应用技术,2006,1:1-4.
[24]宋牟平,汤伟中,周文.拉曼型分布式光纤温度传感器温度分辨率的理论分析.仪器仪表学报,1998,19(5):485-488.
[25]邹江,王殊.分布式光纤测温系统的温度分辨率.激光与红外,2000,30(5):304-306.
[26]彭启琮等.开放式多媒体应用平台--OMAP处理器的原理及应用.北京:电子工业出版社,2005.
[27]肖金锽,殷小贡.基于ARM核和DSP核的OMAP5910嵌入式系统.微型机与应用,2004,12(12):23-25.
[28]何晴,张保平.基于OMAP架构的智能手持设备设计.微处理机,2004,(6):58-60.
[29]彭启琮,管庆等编著.DSP的集成开发环境.北京:电子工业出版社,2004.
[30]Dakin J P.Temperature distribution measurement using Raman ratio thermometry.SPIE Fiber Optic and Laser Sensors,1985,566:249-253.
[31]赵育良,李开端.相机镜头焦距自动测量系统的设计及精度分析.计算机测量与控制,2002,10(4):221-223.
[32]彭玉华.小波变换与工程应用.北京:科学出版社,1999:1-10.
[33]杨福生.小波变换的工程分析与应用.北京:科学出版社,2000:1-4.
[34]徐长发,李国宽.实用小波方法.武汉:华中科技大学出版社,2001:92-95.
[35]邹江,王殊,杨宗凯.小波分解在分布式光纤温度传感测量系统中的应用.红外与激光工程,2001,30(4):231-234.
[36]LiuPin.Wavelet and signal processing.Journal of South-Central University for Nationalities,2001,20(2):23-26.
[37]Rioul o,Vetterli M.Waveletand sigal processing.IEEE,Sigal Process.Mag,1991,10:14-38
[38]戴成龙,宣益民,刘皓明.对噪声淹没的传感信号进行小波分析处理.南京理工大学报,2001,25(4):355-359.
[39]Young R K.Wavelet theory and its application.Boston Kluwei Academic Publisher 1993:120-122.
[40]Mallat S.A theory for multiresolution signal decomposition.The WaveletRepresentation IEEE PAMI,1989,11(7):674-693.
[41]Daubechiesl.The wavelet transform.Time-frequency Localization and SignalAnalysis IEEE,1990,46(5):961-1005.
[42]Rioul O,Vetterli M.Wavelets& signal processingl.IEEE,Signal Process.Mag,1991,10:14.
[43]Zhdanov M S,Traynin P N,Portniaguine O.Resistivity imaging by time domain electromagnetic Migration.Exploration Geophysics,1995,26(5):186-194.
[44]万相奎,徐杜.自适应阈值小波滤波及其在ECG滤波中的应用.计算机工程与应用,2008,18(3):17.
[45]张雄伟.DSP芯片的原理与开发应用(第二版).北京:电子工业出版社,2000.
[46]汪春梅,孙洪波,任治刚.TMS320C5000系列DSP系统设计与开发实例.北京:电子工业出社,2004.
[2]Hartog A H.Distributed temperature sensor based on liquid core optical fiber.IEEE Lightwave Tech,1983,1(3):498-509.
[3]Hartog A H.Distributed temperature sensor in solid core fibers.Electron Lett,1985,21(4):1061.
[4]Horiguchi T.Tensile strain dependence of brillouin frequency shift in silica optical fibers.IEEE Photon.Tech Lett,1989,1(5):107-108.
[5]Culverhouse D.Potential of stimulated brillouin scattering as sensing mechanism for distributed temperature sensors.Tech Lett,1989,25(14):913-915.
[6]Kurshima T,Horiguchi T.Brillouin optical fiber time domain reflectometry.ICICE Trans Commun,1993,76(4):718-721.
[7]Newson T P,Kee H.All-fiber system for simultaneous interrogation of distributed strain and temperature sensing by spontaneous brillouin scattering.Optical Lett,2000,25(10):620-626.
[8]Bao X.Experimental and theoretical studies on a distributed temperature sensor based on brillouin scattering.Lightwave Tech,1995,13(7):55-60.
[9]Dakin J P,Pratt D J.Distributed optical fiber sensors.SPIE,1985,17(9):76-108.
[10]周胜军,刘凤军.分布式光纤温度传感器的原理和应用.半导体光电,1998,19(5):287-290.
[11]黄尚廉,梁大巍.分布式光纤温度传感器系统的研究.仪器仪表学报,1991,12(4):359-364.
[12]张在宣,刘天夫.激光拉曼型分布式光纤温度传感器系统.光学学报,1995,16(11):1585-1589.
[13]张艺,张在宣,金仁诛.远程分布式光纤传感器系统的设计和制造.光电工程,2005,32(4):45-48.
[14]Kersey A D.Fiber grating sensors.Journal of lightwave technology,1997,15(8):1442-1463.
[15]Rao Y J,Jackson D A.A prototype multiplexing system for use with a large number of fiber-optic-based extrinsic Fabry-Perot sensors exploiting low coherence interrogation.SPIE,1995,25(7):90-98.
[16]Ifeachor E C,Jervis B W.Dgital signal processing:a practical approach.USA:Addison Wesley publishing company,1993.
[17]Chan C CShi C Z,Gong J M et al.Enhancement of the measurement range of FBG sensors in a WDM network using a minimum variance shift technique coupled with amplitude-wavelength dual coding.Optics Communications,2003,215(4):289-294.
[18]张岩红.分布式光纤温度传感器信号处理系统的研究与设计:(硕士学位论文).河北省秦皇岛市:燕山大学,2003.
[19]程光煦.拉曼布里渊散射.北京:科学出版社,2001.
[20]史晓锋,李铮,蔡志权.分布式光纤测温系统及其测温精度分析.测控技术,2002,21(1):9-10.
[21]Lees G P.Advances in optical fiber distributed temperaturesensing using the Landau Placzek ratio.IEEE Photonics Technol,1998,10(1):126-128.
[23]倪玉婷,吕辰刚,葛春风,等.基于OTDR的分布式光纤传感器的原理及其应用.光纤与电缆及其应用技术,2006,1:1-4.
[24]宋牟平,汤伟中,周文.拉曼型分布式光纤温度传感器温度分辨率的理论分析.仪器仪表学报,1998,19(5):485-488.
[25]邹江,王殊.分布式光纤测温系统的温度分辨率.激光与红外,2000,30(5):304-306.
[26]彭启琮等.开放式多媒体应用平台--OMAP处理器的原理及应用.北京:电子工业出版社,2005.
[27]肖金锽,殷小贡.基于ARM核和DSP核的OMAP5910嵌入式系统.微型机与应用,2004,12(12):23-25.
[28]何晴,张保平.基于OMAP架构的智能手持设备设计.微处理机,2004,(6):58-60.
[29]彭启琮,管庆等编著.DSP的集成开发环境.北京:电子工业出版社,2004.
[30]Dakin J P.Temperature distribution measurement using Raman ratio thermometry.SPIE Fiber Optic and Laser Sensors,1985,566:249-253.
[31]赵育良,李开端.相机镜头焦距自动测量系统的设计及精度分析.计算机测量与控制,2002,10(4):221-223.
[32]彭玉华.小波变换与工程应用.北京:科学出版社,1999:1-10.
[33]杨福生.小波变换的工程分析与应用.北京:科学出版社,2000:1-4.
[34]徐长发,李国宽.实用小波方法.武汉:华中科技大学出版社,2001:92-95.
[35]邹江,王殊,杨宗凯.小波分解在分布式光纤温度传感测量系统中的应用.红外与激光工程,2001,30(4):231-234.
[36]LiuPin.Wavelet and signal processing.Journal of South-Central University for Nationalities,2001,20(2):23-26.
[37]Rioul o,Vetterli M.Waveletand sigal processing.IEEE,Sigal Process.Mag,1991,10:14-38
[38]戴成龙,宣益民,刘皓明.对噪声淹没的传感信号进行小波分析处理.南京理工大学报,2001,25(4):355-359.
[39]Young R K.Wavelet theory and its application.Boston Kluwei Academic Publisher 1993:120-122.
[40]Mallat S.A theory for multiresolution signal decomposition.The WaveletRepresentation IEEE PAMI,1989,11(7):674-693.
[41]Daubechiesl.The wavelet transform.Time-frequency Localization and SignalAnalysis IEEE,1990,46(5):961-1005.
[42]Rioul O,Vetterli M.Wavelets& signal processingl.IEEE,Signal Process.Mag,1991,10:14.
[43]Zhdanov M S,Traynin P N,Portniaguine O.Resistivity imaging by time domain electromagnetic Migration.Exploration Geophysics,1995,26(5):186-194.
[44]万相奎,徐杜.自适应阈值小波滤波及其在ECG滤波中的应用.计算机工程与应用,2008,18(3):17.
[45]张雄伟.DSP芯片的原理与开发应用(第二版).北京:电子工业出版社,2000.
[46]汪春梅,孙洪波,任治刚.TMS320C5000系列DSP系统设计与开发实例.北京:电子工业出社,2004.