Research On The Method Of Non-contact Human Body Sign Signal Extraction And Separation

Non-contact vital signs monitoring technology is an advanced non-contact radar detection technology,this technology is mainly combined with radar technology and biomedical technology.The technology can be widely used in health monitoring,clinical medical treatment,disaster relief,urban anti-terrorism and other fields.The signal of life sign generally belongs to weak signal.Monitoring of weak signal requires high performance radar and advanced digital signal processing method.According to the blind spot problem in radar signal processing,signal of life's AT(Arctangent)demodulation method is deeply researched.The I/Q dual channel orthogonal receiver is used to solve the blind spot problem in the echo signal.In AT demodulation of dual life signal,we need to preprocess the echo signal.This paper proposed filtering all DC components firstly,then using the circle center estimation method to restore the useful DC component.The simulation results verify the effectiveness of the AT demodulation method.On the basis of accurate AT demodulation of the life signal,the demodulated signal of the chest displacement is processed by signal separation.After comparing three kinds of signal separation algorithms,the EMD algorithm is finally chosen.In order to solve the pattern aliasing problem,an improved EMD algorithm and CEEMD algorithm are proposed.The simulation results verify that the two algorithms can extract heartbeat signals under disturbance and interference,and Hilbert transform can get accurate instantaneous information of heartbeat signal.Finally,this paper use the existing experimental conditions,developed a practical monitoring platform,using CEEMD Hilbert Huang transform to mixed signal processing based on data,and succeed in human respiratory interference and harmonic interference under the jitter extracted heartbeat signals and realize the monitoring of instantaneous heart rate.