Combining Multiple Methods to Improve Beat-to-Beat Interval Length Estimations in Ballistocardiograms

Ballistocardiography is a technique in which the mechanical activity of the heart is recorded. The locations of individual heart beats in ballistocardiograms (BCGs) can be estimated by various methods. We present a novel algorithm to obtain improved estimates of heart beat locations by merging the outputs of multiple beat-to-beat detection methods. For this purpose, the reliability of each individual estimate is assessed. A local greedy heuristic then takes these reliabilities into account to combine the individual estimates. By combining three methods instead of using a single method, the beat-tobeat interval error was reduced from up to 69.29 ms to 14.16 ms. False positive and false negative rates were reduced from up to 1.71% and 7.33% down to 0.13% and 0.28%, respectively.