Fig. 2

AF and NAF BCG signal: 1-s-segment and 24-s-segment are illustrated. The left part in this waveform is labeled as AF period, the right part is labeled as NAF period, and all periods were split manually by medical experts in accordance to the synchronous ECG signal as a reference. In Fig. 2, the 24-s-segment is divided from the original BCG signal, and the 1-s-segment is extracted from the 24-s-segment by means of taking 0.5 s before and 0.5 s after the occurrence of the J-peak in BCG waveform