谱减降噪法在相位敏感OTDR扰动传感系统中的应用
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摘要
针对当前基于相位敏感光时域反射计(Φ-OTDR)的分布式光纤扰动传感系统降噪算法复杂且效果不明显的问题,提出了谱减降噪法。首先对采样信号进行加窗分帧和傅里叶变换;其次取前十五帧无扰动信号功率谱的平均值作为噪声的功率谱估计,用含有扰动信号的功率谱减去噪声的估计谱得到降噪信号的功率谱;最后降噪信号通过逆傅里叶变换得到其时域信号。谱减法运算快且失真小,研究结果表明了在传感距离为53. 6 km的情况下,降噪信号的信噪比提高了2. 7 dB。
Aiming at the problem that the current noise reduction algorithm of distributed fiber-optic disturbance sensing system based on phase sensitive optical time domain reflectometer( Φ-OTDR) is complex and the effect is not obvious,the spectral subtraction method is proposed. Firstly,the sampling signal was windowed and Fourier transformed. Secondly,taken the average of the power spectrum of the undisturbed signal in the first fifteen frames as the power spectrum estimation of the noise,and obtained the power spectrum of the noise reduction signal by subtracting the estimated spectrum of the noise from the power spectrum containing the disturbance signal. The final noise reduction signal obtained its time domain signal by inverse Fourier transform. The spectral subtraction method has fast operation and less distortion. The results show that the signal-to-noise ratio of the denoised signal increases by 2. 7 dB at the sensing distance of 53. 6 km.
Aiming at the problem that the current noise reduction algorithm of distributed fiber-optic disturbance sensing system based on phase sensitive optical time domain reflectometer( Φ-OTDR) is complex and the effect is not obvious,the spectral subtraction method is proposed. Firstly,the sampling signal was windowed and Fourier transformed. Secondly,taken the average of the power spectrum of the undisturbed signal in the first fifteen frames as the power spectrum estimation of the noise,and obtained the power spectrum of the noise reduction signal by subtracting the estimated spectrum of the noise from the power spectrum containing the disturbance signal. The final noise reduction signal obtained its time domain signal by inverse Fourier transform. The spectral subtraction method has fast operation and less distortion. The results show that the signal-to-noise ratio of the denoised signal increases by 2. 7 dB at the sensing distance of 53. 6 km.
引文
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[15]王路露,夏旭,冯璐,等.基于频谱方差和谱减法的语音端点检测新算法[J].计算机工程与应用,2014,50(8):194-197.
[2] TAYLOR H F,JUAREZ J C. Distributed Fiber Optic Intrusion Sensor System[J]. Journal of Lightwave Technology,2005,23(6):2081-2087.
[3] MARTINS H F,MARTINSLOPEZ S,CORREDERA P,et al. Phase-sensitive Optical Time Domain Reflectometer Assisted by First-order Raman Amplification for Distributed Vibration Sensing Over>100 km[J]. Journal of Lightwave Technology,2014,32(8):1510-1518.
[4] MARTINS H F,MARTINSLOPEZ S,CORREDERA P,et al. Comparison of the use of first and second-order Raman amplification to assist a phase-sensitive optical time domain reflectometer in distributed vibration sensing over 125 km[C]//International Conference on Optical Fibre Sensors.International Society for Optics and Photonics, 2014:91576.
[5] MARTINS H F,MARTINSLOPEZ S,CORREDERA P,et al. Distributed Vibration Sensing Over 125 km With Enhanced SNR Using Phi-OTDR Over a URFL Cavity[J].Journal of Lightwave Technology,2015,33(12):2628-2632.
[6] ZHU T,BAO X Y. Vibration monitoring with high frequency response based on coherent phase-sensitive OTDR method[J]. Proceedings of SPIE-The International Society for Optical Engineering,2011,7753(17):1-714.
[7] BAO X Y,CHEN L. Recent progress in distributed fiber optic sensors[J]. Sensors,2012,12(7):8601-8639.
[8] QIN Z,CHEN L,BAO X Y. Wavelet Denoising Method for Improving Detection Performance of Distributed Vibration Sensor[J]. IEEE Photonics Technology Letters,2012,24(7):542-544.
[9] LU Y. Pencil-lead-break transient detecting by phase-optical time domain reflectometer based on coherent detecting[C]//International Conference on Optoelectronics and Microelectronics. IEEE,2013:224-226.
[10]尚静,杨德伟,李立京,等.小波阈值降噪法在Φ-OTDR扰动传感系统中的应用[J].现代电子技术,2012,35(17):51-53.
[11] SHI Y,FENG H,AN Y,et al. Research on wavelet analysis for pipeline pre-warning system based on phase-sensitive optical time domain reflectometry[C]//Ieee/asme International Conference on Advanced Intelligent Mechatronics. IEEE,2014:1177-1182.
[12]崔洪亮,刘野,于淼,等.小波降噪在分布式光纤干涉振动检测及定位系统中的应用[J].光学精密工程,2015,23(10z):71-76.
[13] XU C J,YE W. Optical fiber vibration identification system based on phi-OTDR technology and optical fiber vibration identification method thereof:CN,106225907 A[P]. 2016.
[14] BOLL S. Suppression of acoustic noise in speech using spectral subtraction[J]. Acoustics,Speech and Signal Processing[J],IEEE Transactions on,1979,27(2):113-120.
[15]王路露,夏旭,冯璐,等.基于频谱方差和谱减法的语音端点检测新算法[J].计算机工程与应用,2014,50(8):194-197.