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Table 1: Mean of heartbeats [BPM] measured by the ECG and the proposed US system.
Subject 1 Subject 2 Subject 3 Subject 4
Acq.1 Acq.2 Acq.1 Acq.2 Acq.1 Acq.2 Acq.1 Acq.2
ECG 64.10 65.55 57.28 58.04 67.30 70.07 56.74 63.83
US 64.10 65.55 57.28 58.18 67.42 70.09 56.80 63.89
and the ones by means of the prototype are presented
in Table 1. The table shows that the results obtained
by the proposed system are very similar to the ones
obtained by reference ECG with a very low error
(maximum absolute error of 0.12 s).
5 CONCLUSIONS
This manuscript presents a US prototype for non-
contact heartbeat detection. The system measures
skin displacement due to the pressure waves gen-
erated by the cardiac activity and exploits a multi-
channel architecture to overcome the null-point issue
and a windowing procedure for enforcing the heart-
beat detection. The prototype was built and tested on
four volunteers. Results are encouraging, as the sys-
tem was able to provide a performance level in detect-
ing heartbeats comparable to standard electrocardio-
graphy. Further work will focus on the improvement
of system robustness to subject movements and ex-
ternal artifacts, as well as on increasing the working
distance of the system.
ACKNOWLEDGEMENTS
The work has been partially supported by the funding
program “Bando di sostegno alla ricerca individuale
per il triennio 2015-2017” of the University of Napoli
Parthenope.
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