Fig. 1. Flow chart of feature extraction and classification for optical fiber vibration signal

Fig. 2. Decomposition flow chart of LMD and EMD methods

Fig. 3. Time domain diagram and spectrogram of x(t). (a) Time domain diagram; (b) spectrogram

Fig. 4. Instantaneous amplitude and frequency obtained by different methods. (a) LMD method; (b) EMD method

Fig. 5. Decomposition results of different methods. (a) LMD method; (b) EMD method

Fig. 6. Two-dimensional feature distribution map of the signal

Fig. 7. Signal reconstructed by LMD method. (a) Car cross signal; (b) electric pick signal; (c) noise; (d) pickaxe signal

Fig. 8. Sample entropy and energy distribution of LMD. (a) Car cross signal; (b) electric pick signal; (c) noise; (d) pickaxe signal

Fig. 9. Flow chart of the classification and identification method

Fig. 10. Confusion matrices for different methods. (a) LMD method; (b) EMD method

Fig. 11. Optical fiber signal recognition accuracy of different methods