A scheme is proposed for the identification of surface intrusion events, from signals detected by an ultra-weak fiber Bragg grating array in a subway tunnel. The spectral subtraction and the root mean square of the power spectral density are combined to extract event signals. The local characteristics-scale decomposition and the multi-scale permutation entropy are employed subsequently for feature extraction, which can improve the event recognition rate from the perspective of multi-scale analysis. Experimental demonstration verifies that the proposed scheme can identify four common events. Among the events, the discrete pulse construction and the continuous pulse construction on the ground surface are intrusion events, the subway train traveling in the tunnel and the lorry passing on the ground surface are non-intrusion events. The average recognition rate of 96.57% is achieved, which can satisfy actual application requirements.

中文翻译：

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基于超弱FBG阵列的光纤传感在地铁隧道表面入侵事件识别中的应用

提出了一种从地铁隧道中的超弱光纤布拉格光栅阵列检测到的信号中识别表面入侵事件的方案。频谱减法和功率频谱密度的均方根被组合以提取事件信号。随后采用局部特征尺度分解和多尺度置换熵进行特征提取，从多尺度分析的角度出发，可以提高事件识别率。实验演示验证了所提出的方案可以识别四个常见事件。在这些事件中，在地面上的离散脉冲构造和连续脉冲构造是侵入事件，在隧道中行驶的地铁列车和在地面上通过的卡车是非侵入事件。