Third-order cumulant signature matching technique for non-invasive fetal heart beat identification

This paper utilises the distinctive transient pulse feature of the third-order cumulant diagonal slice (TOCDS) of ECG signals to detect the number of occurrences of fetal heart beats during each of the maternal cycles. The fetal ECG signal is a comparatively weak signal (less than 20 percent of the mother ECG) and often embedded in noise. The fetal heart rate (FHR) lies in the range from 1.3 Hz to 3.5 Hz and it is possible for the mother and some of the fetal ECG signals to be closely overlapping. The paper also addresses the problem of false alarm situations often arising in diagonal-cumulant-slice recording during labour due to non-Gaussian impulsive or transient noise types and shows some results obtained after Volterra noise whitening and interpolation of the neighbouring fetal TOCDS samples.