一种用于光纤周界安防系统的端点检测方法

为了提高光纤周界安防系统中扰动信号端点检测的 性能,提出一种新型端点检测方法。首先通过计算信号 的短时能量和过零率分布分别找出信号中短时能量比和过零率满足一定门限的信号点,通过 对这两信号点 进行一定的加权确定扰动信号的端点位置。与离散小波提取起始点信号相比,本文方法由于 综合了短时能量 和过零率法的优势,能够适应更多的扰动事件类型,通过加权极大提高了端点检测的精度 ,并且运算时 间大幅降低,提高了系统的实时性。实验结果表明,本文算法在10M Hz的采样速度和采集0. 3s数据情况下,93.47%的数据定位误差低于10m,计算时间少于0.3s。

An endpoint detection method for fiber perimeter security system

Fiber perimeter security system based on dual Mach-Zehnder interferom eter (DMZI) is a kind of sensor system that uses fiber as the sensing media.The endpoint detection in the fiber perimeter security system can confirm the start of the disturbance signal,which is the ba sis of disturbance position calculation and action mode judging.In order to improve the performance of the disturbance signal endpoint detection and the accuracy of position,this paper presents a novel end point detection method. First,through calculating the short-term energy and zero-crossing rate of the signal,the signal points which can meet some thresholds are found respectively.And then by weighing the t wo signal points,the endpoint of the disturbance signal can be obtained.Compared with the discrete wavelet me thod,this method analyzes short-term energy and zero-crossing rate synthetically,and is able t o accommodate more types of disturbance events,improving the precision of endpoint detection great ly and reducing the computation time significantly.Experimental results show that the method achieves that 93.47% of the position error is less than 10m with calculation time less than 0.3s,in the case of 10MHz sampling rate and 0.3s signals.