基于互相关卷积与高阶矩质心计算的布里渊散射谱特征提取  

Feature Extraction of Brillouin Scattering Spectrum Based on Cross-Correlation Convolution and High-Order Centroid Calculation

作　　者：尚秋峰[1] 胡雨婷 刘薇 

机构地区：[1]华北电力大学电气与电子工程学院,河北保定071003

出　　处：《中国激光》2017年第11期235-242,共8页Chinese Journal of Lasers

基　　金：国家自然科学基金(61377088);河北省自然科学基金(F2014502098)

摘　　要：针对目前布里渊光时域分析(BOTDA)分布式光纤传感系统存在的实时性较差的问题,为了缩短测量时间,提出一种基于互相关卷积与高阶矩质心计算相结合的布里渊散射谱特征提取方法。首先将布里渊散射谱沿光纤的扫频数据与理想Lorentz曲线作互相关卷积,然后利用卷积结果峰值附近的理想Lorentz线型特征进行高阶矩质心提取,并将提取结果作为布里渊频移(BFS)的估计值;其次,搭建1.5km的瑞利BOTDA温度传感系统对所提算法进行可行性验证。结果表明:不同于常用的Lorentz拟合(LCF),所提算法避免了复杂的迭代求解所造成的测量时间延长,具有良好的实时性与测量精度,选取恰当的数据点数与阶数可将误差控制在小于1 MHz;当进行长距离高分辨率的动态测量而不得不加大扫频间隔以减少测量时间时,所提算法的测量误差远小于基于莱文伯-马奈特(LM)算法的LCF的测量误差。Aiming at the problem of poor real-time performance of Brillouin optical time domain analysis （BOTDA） distributed optical fiber sensing system, we propose a extraction method of Brillouin scattering spectrum feature based on the cross-correlation convolution and high-order centroid calculation to reduce measuring time. Firstly, the sweep data of the Brillouin scattering spectrum along the optical fiber is convoluted with the ideal Lorentz curve, and the convolution result has a nearly ideal Lorentzian distribution around its peak. Then we carry out high-order centroid extraction, and take the extracted result as an estimated value of Brillouin frequency shift （BFS）. A 1.5 km Rayleigh BOTDA temperature sensing experiment is designed to verify the feasibility of the proposed algorithm. The results show that the proposed algorithm is different from the conventional Lorentz curve fitting （LCF）, it avoids extension of measuring time caused by the complex iterative process, and has good real-time performance and measurement accuracy. The proper selection of data point numbers and calculation orders can control the error within 1 MHz. When the sweep interval has to be increased to reduce the measurement time in long-range and high- resolution dynamic measurement, the proposed algorithm has a smaller measurement error than the LCF based on the Levenberg-Marquardt （LM） algorithm.

关 键 词：散射 布里渊光时域分析 互相关卷积 布里渊散射谱 质心计算 高阶矩 

分 类 号：TN247[电子电信—物理电子学]