针对传统故障识别方法过程复杂、用时长、准确率低等问题,提出了一种基于小波包分析和支持向量机的光纤故障自动识别方法。对光时域反射仪采集的数据进行事件点定位,选择最优基小波和尺度完成事件信号的分解和重构,提取归一化的小波包能量作为事件信号的特征向量;建立支持向量机模型,将特征向量作为输入进行训练和测试,最终实现故障识别。实验对机载光缆中由连接器引起的反射事件和弯折引起的非反射事件进行二分类测试,总样本数为2500。实验结果表明,当训练样本数为1750,测试样本数为750时,该方法对机载光纤中反射事件和非反射事件的正确识别率为99%,耗时3.03 s;与基于反向传播神经网络的识别方法相比,准确率提升了2%,且耗时仅为其1%左右。目前已成功应用于自主研发的机载光缆组件外场检测设备。

As traditional fault identification methods typically exhibit considerable processing complexity, are often time-consuming, and display a low degree of precision, a novel approach based on wavelet packet analysis using a support vector machine (SVM) is proposed in this study for the automatic identification of fiber defects in optical time domain reflectometry (OTDR). OTDR is initially used to acquire the original data of the fiber under test (FUT). Further, the event signs are decomposed by the optimal basic wavelet packet after the events are located, and the normalized energy features of the event signs as eigenvectors are extracted as input of training and testing based on the results of signal reconstruction. Finally, the SVM model is built,and fiber defects can be identified with the eigenvector as input. Subsequently, the SVM identification technique is used to obtain effective classification of the events as either reflection events, which are caused by connectors, or as non-reflection events, which are caused by bent events. In this study, two classification tests have been performed on a total of 2500 reflection and non-reflection events in airborne optical cable samples. The experimental results indicate that our method achieves a recognition rate of 99% in 3.03 s when the number of training samples is 1750 and when the number of testing samples is 750. Additionally, the recognition rate is increased by 2% and the recognition time is observed to be only 1% when compared to the previously proposed recognition method that is based on the backpropagation neural network. At present, the proposed method is successfully applied in the field detection equipment of airborne optical cable components independently developed.