Robust detection of background noise in phonocardiograms

In this paper we present a method for detecting external and internal noises that can corrupt the phonocardiogram (PCG). Using a reference signal from an accessory microphone placed on the stomach, the method first spectrally enhances this signal and then applies short-term log energy (STLE) to detect the noise. We also propose a robust method to determine a decision threshold to detect noise using the STLE. Our results show that spectral enhancement combined with STLE can efficiently detect noises, external and internal, that can corrupt the PCG.