摘要
相位敏感型光时域反射仪(φ-OTDR)有着灵敏度高、抗电磁干扰、传输距离长等优点,在轨道交通、管道监测、海洋声信号检测、周界安防等领域都有着广泛的应用.然而,φ-OTDR系统的性能容易受激光器噪声、平衡光电探测器噪声、掺铒光纤放大器噪声、环境噪声等因素的影响.在现有小波去噪算法的基础上,通过使用每层小波变换中的小波系数作为阈值计算的参数,提出了一种新的自适应阈值计算方法和连续性低误差小波阈值函数,并对新的小波阈值函数性能进行了分析.实验结果表明,与小波软、硬阈值去噪算法相比,所提出的改进自适应小波阈值去噪算法有更好的去噪效果.
Abstract
Phase-sensitive optical time-domain reflectometry(φ-OTDR)offers advantages such as high sensitivity,resistance to electromagnetic interference,and long transmission distance,and is widely used in fields such as rail transit,pipeline monitoring,marine acoustic-signal detection,and perimeter security.However,the performance of φ-OTDR systems is affected by laser,balanced photodetector,erbium-doped fiber amplifier,and environmental noises.Based on existing wavelet denoising algorithms,this study proposes a new adaptive threshold-calculation method and a new continuous low-error wavelet-threshold function using the wavelet coefficients in each layer wavelet transform as parameters for threshold calculation,as well as analyzes the performance of the new wavelet-threshold function.Experimental results show that compared with wavelet soft-and hard-threshold denoising algorithm,the improved adaptive wavelet-threshold denoising algorithm proposed herein offers better denoising effect.
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