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%.