FBG反射谱数据滑动相关滤波算法设计与实现  

Design and implementation of sliding correlation filtering algorithm for FBG reflectance spectra data

作　　者：马嘉仪 张旭 李红[1,2,3] 朱云鸿 董明利 MA Jiayi;ZHANG Xu;LI Hong;ZHU Yunhong;DONG Mingli(Key Laboratory of the Ministry of Education for Optoelectronic Measurement Technology and Instrument,Beijing Information Science&Technology University,Beijing 100192,China;Beijing Laboratory of Optical Fiber Sensing and System,Beijing Information Science&Technology University,Beijing 100016,China;Guangzhou Nansha Intelligent Photonic Sensing Research Institute,Guangzhou 511462,China)

机构地区：[1]北京信息科技大学光电测试技术及仪器教育部重点实验室,北京100192 [2]北京信息科技大学光纤传感与系统北京实验室,北京100016 [3]广州南沙光子感知技术研究院,广东广州511462

出　　处：《红外与激光工程》2024年第6期146-158,共13页Infrared and Laser Engineering

基　　金：国家自然科学基金项目(52375524);北京学者计划项目(BJXZ2021-012-00046)。

摘　　要：针对光纤光栅解调系统中现有滤波算法计算速度与滤波效果难以兼顾的问题,提出了一种基于滑动相关滤波的光纤布拉格光栅(Fiber Bragg Grating,FBG)反射谱滤波方法并在现场可编程门阵列(Field Programmable Gate Array,FPGA)上实现算法加速设计。该算法根据FBG半峰全宽确定高斯函数二阶导数的标准差,用函数的负数作为滤波模板权重,通过滑动数据窗口进行反射谱数据与滤波模板的相关计算,从而实现滤波操作。使用该算法处理含高斯噪声、坏点和基线的仿真数据,验证了该方法对多种异常反射谱数据处理的有效性,并与其他下位机滤波算法进行对比分析,该算法能较好地保留原始数据特征,有较好的鲁棒性,信噪比最高提升28.23dB,中心波长平均偏差和偏差标准差最小,分别为1.712 pm和2.996pm。同时在FPGA片上平台实现了该算法,采用循环队列策略设计存储器,提高了存储器使用率,降低了资源消耗。实验表明,该算法可以有效校正多种异常FBG反射谱,在100MHz系统时钟下处理一个反射谱数据所需时间仅5.09μs,易于实现工程化应用,克服了下位机现有滤波算法对FBG反射谱中坏点、基线抑制作用较差和滤波后信号变形的问题,实现了FBG反射谱滑动相关滤波算法的加速设计。Objective The fiber Bragg grating sensing system,with its advantages of electromagnetic interference resistance,lightweight,and high-temperature resistance,has been widely used in structural health monitoring,aerospace,biomedical,and marine engineering fields.However,due to external factors,FBG reflected spectrum data often suffer from Gaussian noise,bad points,and baseline interference,leading to significant errors in central wavelength calculations.Although data filtering on the host computer software has good noise reduction effects,it is difficult to meet the real-time demodulation requirements in industrial applications.Moreover,the commonly used algorithms on the lower computer are limited by the measurement range,which cannot be applied to spectrum filtering of multiple abnormal reflections,and have low signal-to-noise ratio and poor key information extraction capabilities,as well as poor robustness.Methods To address the limitations of lower machine filtering algorithms,a novel FPGA-accelerated processing method for FBG reflection spectra,grounded in sliding correlation filtering,is proposed.The characteristics and origins of FBG abnormal reflection spectra are scrutinized,and the standard deviation of the second derivative of the Gaussian function is meticulously determined,predicated on the half-width of the FBG peak.The filter template length is calculated using sensor sampling compensation,and the negative values of the function are employed as the filter template weights.The spectrum data is correlated with the filter template through a sliding data window.A designed sliding correlation filtering processing module is crafted,and a devised circular queue strategy is employed to design storage memory.This crafted algorithm is implemented on the FPGA.Results and Discussions To assess the efficacy of the sliding correlation filtering algorithm in denoising various FBG abnormal reflection spectra,the algorithm was applied to process simulated signals containing varying levels of Gaussian noise,bad points,

关 键 词：滑动相关滤波 光纤光栅传感 FBG滤波 FPGA 

分 类 号：TN253[电子电信—物理电子学]