Fading-Induced Phase-Fluctuation Reduction and SNR Enhancement in ϕ-OTDR Using Video Block-Matching 3-D Collaborative Processing
Coherent fading and random background noise are two major factors that degrade phase stability and weak-vibration detection in distributed acoustic sensing (DAS) systems. Coherent fading induces local amplitude fading and phase-demodulation instability, whereas random background noise obscures vibration responses and l...