De-noising of wayside acoustic signal from train bearings based on variable digital filtering.

Highlights: [•] An effective de-noising method for ADBD system is proposed. [•] The Morse acoustic theory and variable digital filters are applied to this method. [•] This method could extract useful information in a heavy noise background. [•] Method could deal with multi-source acoustic signals with Doppler Effect. [•] Proposed method has been verified by simulation and experimental cases. [ABSTRACT FROM AUTHOR]