摘要:
在光纤周界安防系统中,急需对入侵事件实现准确而高效的识别,对事件特征做简练而恰当的描述是其关键所在.本文提出一种基于综合特征的入侵事件识别方法,该方法引入全相位滤波器组将输入信号并行分解为多个频率通道,以提取这些通道的归一化功率值;进而与信号过零率相结合,构成包含时域信息、频域信息的综合特征向量;最后将该特征向量馈入径向基函数神经网络即可准确识别出攀爬、敲击、晃动、剪切四种常见的入侵动作.实验证明,本文方法相比于现有的经验模态分解方法,不仅提高了精度,而且显著加快了识别速度.
Abstract:
In an optical fiber perimeter security system, due to the fact that a large quantity of samples are collected in the pro-cess of data acquisition, this heavy data burden inevitably degrades the efficiency and accuracy of intrusion recognition. Hence, it is urgent to remove the redundancy of the collected data records, which essentially requires to describe event features in a concise and proper way. In this paper, we propose a synthesized feature based intrusion recognition method, which is especially suitable to describing the fiber intrusion vibration signals with both wide bandwidth and high nonsta-tionarity. Firstly, the all-phase filter bank characterized by large sidelobe attenuation and high flexibility of coefficient configuration, is employed to parallelly divide the input signal into multiple frequency channels, from which the power values can be accurately calculated. Secondly, the crossing rate of the input signal is combined with these power values to construct a synthetical feature vector, in which both the time-domain information and frequency-domain information are incorporated together. Finally, these synthetical feature vectors are fed into a radial-basis-function network based classifier to recognize 4 common intrusions (climbing, knocking, waggling and cutting). Essentially, the high efficiency of our proposed scheme lies in the parallel pipeline mode of the configurable filter bank and simple calculation of features, which facilitates speeding up the intrusion recognition. The high accuracy of our proposed scheme lies in two aspects:1 the all-phase filter bank possesses small inter-channel interference, which helps to reduce the inter-coupling between output power values; 2 the synthesis of both frequency-domain information and time-domain information ensures the completeness of feature description. Experiments show that the sensing range of the proposed scheme can reach 2.25 km. Moreover, compared with the empirical mode decomposition based method, the proposed method not only improves the precision, but also significantly speeds up the recognition.