Fetal phonocardiogram extraction using single channel blind source separation

Frequent and long-term monitoring of fetal health status is still a challenging task in high-risk pregnancies. This paper presents a fully noninvasive method to extract fetal heart sound (FHS) from acoustic signals recorded from the maternal abdominal surface. The proposed algorithm is based on single channel blind source separation (SCBSS), which utilizes empirical mode decomposition (EMD) and nonnegative matrix factorization (NMF) to extracts different sources from audio signal mixtures. To evaluate the algorithm performance, a dataset of 110 pregnant women were collected at Hafez Hospital of Shiraz University of Medical Sciences. The algorithm performance has been tested on 50 randomly selected sample data of recording signals. The results show very good separation of the fetal heart sound. Quantitative results show that the fetal heart rate (FHR) calculated from the processed channel corresponding to the fetal phonocardiogram (fPCG) has an accuracy of 96% as compared to the simultaneously recorded FHS by means of ultrasound.