Fig. 1. Distribution of scattered light in optical fiber

Fig. 2. Schematic of the structure of the coherent detection type φ‑OTDR system

Fig. 3. Random forest model

Fig. 4. Signal acquisition and processing process

Fig. 5. Schematic of system layout

Fig. 6. Photo of fiber optic splice point

Fig. 7. Two‑dimensional distribution of vibration

Fig. 8. Random forest algorithm test results

Fig. 9. Linear regression algorithm test results

Fig. 10. MSE and correlation coefficient histogram