Research On Respiration And Heartbeat Detection Algorithm Based On Ultra-wide Band Radar

With the development and maturity of radar technology,the application of radar technology to human breathing and heartbeat detection has become a research hotspot.Ultra Wide Band(UWB)signal has the advantages of strong penetration,low signal attenuation,and high resolution,therefore,the breathing and heartbeat detection based on UWB radar has extremely high research value and realistic meaning in disaster rescue,military and police applications,medical health,and so on.In this paper,firstly the UWB technology is introduced in detail and the echo signal model reflected by the human body is established.Aiming at the problem that the respiratory and heartbeat signal is very weak and easy to be submerged in background clutter and noise,the background clutter elimination method is used to remove these clutter and noise.The echo signal reflected by the human body is extracted from the echo matrix by variance analysis,and the trend component is fitted and eliminated by the least square method.In order to eliminate the interference of signals in other frequency bands,elliptical low-pass and band-pass filters are designed to improve the signal-to-noise ratio of the signal.Aiming at the problem that breathing harmonics and heartbeat signals are difficult to separate,a new breathing and heartbeat detection algorithm based on fast independent component analysis and ensemble empirical mode decomposition is proposed in this paper.Firstly,the echo signals of multiple channels are used as observation signals for independent component analysis,and the source signal with the largest signal energy is selected as the target signal from the separated source signals.Then,the ensemble empirical mode decomposition is used to separate the target signal into multiple modal components,the false components are eliminated through correlation analysis.Finally,the breathing and heartbeat signals are reconstructed from the remaining components.Experiments show that compared with the empirical wavelet transform and the ensemble empirical mode decomposition threshold reconstruction method,the respiratory and heartbeat signals obtained by this method are cleaner.In order to further eliminate the interference of respiratory harmonics on the heartbeat signal,another new respiratory and heartbeat detection algorithm based on variational modal decomposition(VMD)and differential evolution algorithm is proposed in this paper.The algorithm uses the differential evolution algorithm to search for the best parameters of the VMD,at the same time,the respiratory harmonic modes from the modal components obtained by the VMD are selected and removed.Finally the breathing and heartbeat signals are reconstructed from the modal components.Experiments show that this new algorithm can eliminate the interference of breathing harmonics on the heartbeat signal with high-precision detection of breathing signals and heartbeat signals.