A combined heartbeat detector based on individual BCG and IPG heartbeat detectors

This paper presents a preliminary approach for heartbeat detection on a weighing scale, using a combined heartbeat detector and an ensemble method. First, two independent sub-detectors are implemented based on the BCG (Ballistocardiogram) and lower-body IPG (Impedance Plethysmogram) signals. Then, the results of these sub-detectors are combined using a higher level decision maker. The BCG, which describes the reaction of the body to cardiac ejection of blood, was measured using the strain gauges in a modified commercial weighing scale. For the lower-body IPG, a small amount of current was injected into the subject through the electrodes under the subject's toes, and the resulting differential voltage across the heels was measured. We tested our method on the first 30 seconds of the BCG and IPG signals collected from 8 subjects. The results show the combination significantly improved over individual detector, with a resulting interval accuracy of 97%.