Blind source separation to extract foetal heart sounds from noisy abdominal phonograms: A single channel method

A method for extracting foetal heart sounds (FHS) from noisy single channel abdominal phonograms is proposed. First, an appropriate matrix of delays is constructed; then multiple independent components are calculated using FastICA; finally, components are projected back onto the measurement space and those associated to FHS are subjectively selected. Three single channel phonograms, obtained from different subjects were analysed. Preliminary results are promising and showed successfully extractions of FHS (S1, S2). Future work will increase the number of subjects, evaluate the extraction quality, look for more information about foetal well-being, find an objective way to select FHS, and explore ICA implementations that utilise temporal structure such as Temporal Decorrelation source SEParation (TDSEP).