Optical fiber perimeter signal recognition based on fast dynamic time warping

In order to improve identification rates (IRs) of signal recognition for optical fiber perimeter defense systems, a novel signal recognition method based on the fast dynamic time warping (FastDTW) algorithm and nearest neighbor criterion is proposed. The distributed optical fiber sensing system based on an in-line Sagnac interferometer is employed as a simulated perimeter defense system to acquire three different kinds of sensing output signals. The signals are divided into several signal segments according to their categories and selected as reference templates and test samples, respectively. The FastDTW can calculate the optimal warping path distance between the test sample and each reference template. The signal recognition results are obtained according to the nearest neighbor criterion. The experimental results show that the average IR of the three kinds of sensing signals is above 99%. The proposed recognition method does not need special training process, hence is simple, and easy to implement. It can achieve a high identification rate under small sample condition which provides a new approach for the signal recognition of optical fiber perimeter defense systems.