The Lost-K and Shorter-J Phenomenon in Non-Standard Ballistocardiography Data

Non-standard ballistocardiogram(BCG) data generally do not have prominent J peaks. This paper introduces two phenomena that reduce the prominence of Jpeaks: the shorter-J phenomenon and the lost-K phenomenon, both of which are commonly observed in non-standard BCG signals . This paper also proposes three signal transformation methods that effectively improve the lost-K and shorter-J phenomena. The methods were evaluated on a time-aligned ECG-BCG dataset with 40 subjects. The results show that based on the transformed signal, simple J-peak-based methods using only the detection of local maxima or minima show better performance in locating J-peaks and extracting BCG cycles, especially for non-standard BCG data.