Reserch On Breath And Heartbeat Stochastic Resonance Detection Based On Millimeter Wave Radar

Vital sign testing is a current medical diagnostic method,and non-contact testing is highly favored by the public due to its more convenient and comfortable experience.It is widely used in healthcare and other health fields.The vital sign detection based on millimeter wave radar has the function of both ranging and velocity measurement,which can distinguish different targets and remove noise information through distance information.This article uses TI’s IWR1642 continuous frequency modulation radar to obtain vital sign information through chest displacement changes for respiratory and heartbeat detection.Firstly,this article analyzes the characteristics of respiratory and heartbeat information and the detection principle of millimeter wave radar.Two transmitter and four receiver radars are used for data collection,and the radar echo signal is post-processed.Through analysis,a mathematical model is established to describe the changes in chest displacement and the phase of the echo signal.Secondly,the intermediate frequency(IF)signal is preprocessed.Firstly,the dynamic target detection method is used to remove static environmental clutter,and the distance unit where the human chest is located is determined through distance FFT calculation.The phase information obtained through the distance unit is deconvoluted and pulse noise is eliminated to extract the phase difference signal.Thirdly,digital filters are used to remove the interference of respiratory harmonics,and variational mode decomposition(VMD)algorithm is used to separate and extract respiratory and heartbeat signals.In order to further enhance the vital sign signal,a bistable Stochastic resonance system model with optimized parameters is proposed.Differential evolution algorithm is selected to optimize the parameters of Stochastic resonance system,and the algorithm selects appropriate parameters to enhance and amplify the target signal.By comparing the Stochastic resonance system method of parameter optimization with the real vital sign data,the effectiveness and stability of the method proposed in this paper are verified.Finally,millimeter wave radar and data acquisition board are used to test the performance of the system proposed in this paper.The experimental results show that the parameter optimized Stochastic resonance system proposed in this paper can stably realize the enhancement and waveform recovery of the respiratory and heartbeat signals,and can achieve stable detection from different distances,no experimenters,and the range from 0 °to 90 °,even if the estimation error of the respiratory signals under the state of motion does not exceed 2.3 times/minute,The estimation error of the heartbeat signal shall not exceed 2.2 beats per minute.