Extraction Method of Fetal Phonocardiogram Based on Lifting wavelet analysis

Abstract

Long-term monitoring of fetal health status is important for high-risk pregnancies. In order to extract the pure fetal phonocardiogram(fPCG) and increase the calculating accuracy of fetal heart rate (FHR), a combination of Empirical Mode Decomposition (EMD), Cepstrum, Lifting Wavelet (LWT) and Hilbert transform (HT) method was proposed. First, the heart sound signal was decomposed into finite intrinsic mode functions (IMF) by EMD, and then the signal de-noising was implemented by LWT. Second, the envelope of the signal was obtained by HHT. Finally, the fetal heart rate was obtained by cepstrum analysis. The simulation result shows that the fetal heart rate extracted by this integrated signal processing method is right, and it enhances the precision of fetal heart rate greatly. The wavelet de-noising technology can reduce the noise very well with small computation. It is concluded that this integrated signal method is capable of extracting feature from fPCG.