A Remote Detection Of Human Heart Activity Based On Doppler Radar

In the field of health care,most medical instruments used to measure human heart activity rely on contact electrodes,such as electrocardiograms.This kind of contact measurement method is destined to cause a lot of inconvenience,and will limit its application range.At the same time,theoretically,it is a very difficult challenge to obtain ?V-level bioelectric signals wirelessly and remotely through ECG equipment.So wireless remote cardiogram measurement has great practical significance.Due to its natural non-contact sensing advantages,Doppler radar sensors have attracted many workers to study in depth in recent years.However,since the mechanical motion of the heart is an extremely weak motion,the motion fluctuation is about 100 ?m.Numerous obstacles are faced in terms of DRS-based human heart cardiogram detection in both hardware architecture aspect and signal processing scope.In order to solve the above problems,a high-sensitivity and linearity 24 GHz Doppler radar system was designed and implemented in this study,and the performance of the system was quantitatively analyzed through experiments.The designed hardware system cooperates with a highly robust DC offset compensation algorithm proposed in this study,and can finally achieve a linear recovery of 4 ?m displacement.The further experiment is to monitoring the cardiogram on spot.An electrocardiogram device was also utilized simultaneously for verification.Comparison with human MRI images,it was found that the radar designed in this paper can detect Doppler cardiogram(DCG)at a distance of 1 meter,which actually is the weak displacement of the chest skin caused by the combined atrial and ventricular motion.This kind of cardiogram can provide all the time information of P wave,QRS wave and T wave in ECG.At the same time,it also contains information about the speed and intensity of heart movement that cannot be obtained in the electrocardiogram.Finally,based on an improved cross-correlation filtering algorithm proposed by this study,a high-precision extraction of the R-R interval of the human resting heartbeat was achieved.The huge application potential of this radar in the field of sleep staging is described.