Study On Detection And Data Processing Methods Of Pulse Wave Signals

When the heart contracts and relaxes,the arterial wall contracts and expands,and the flow of blood from the left ventricle into the artery will propagate along the arterial blood vessels in the form of wave,which is the pulse wave.The waveform of the pulse wave contains abundant information of human cardiovascular system,so it is widely concerned in the monitoring of cardiovascular health.Non-invasive extraction of human pulse signals and accurate and effective analysis of them are of great value in the diagnosis and health monitoring of cardiovascular diseases.In this thesis,a pulse wave detection system based on pressure sensor was developed,and the processing methods of the pulse wave signal data was studied.the non-invasive detection of hemodynamic parameters of the cardiovascular system was realized.The main contents are as follows:(1)The research background,significance and the development status of detection and analysis methods of the pulse wave signal at home and abroad were introduced,the formation mechanism were analyzed,the characteristic points and physiological significance of pulse wave,the characteristics of pulse wave signal and some noises which are easy to get in the process of acquisition were elaborated.(2)A pulse wave signal detection system was builded.The system selected the HK-2000B type PVDF piezoelectric membrane pulse wave sensor to collect the pressure pulse wave signal of the human radial artery.After processing the hardware circuit,the signal was collected by the USB-6009 data acquisition card and sent to the upper computer for subsequent processing.The pulse wave acquisition and storage system based on LabVIEW was designed in the machine.(3)In the upper computer MATLAB platform,according to the characteristics of the pulse wave signal and noise characteristics,we used improved wavelet decomposition and reconstruction method to denoise the collected noisy pulse wave signal,and the pulse wave that removed the high-frequency noise and the baseline drift was obtained,and the denoising effect was evaluated.(4)The feature points of the de-noised pulse wave was identified,and an improved method based on waveform time domain features and primary differential recognition was proposed.The three feature points of pulse wave were identified and verified by experiments.Through experimental verification,the accuracy of the aortic opening point(point b)was 99.80%,and the recall rate was 99.97%.(5)We collected the pulse wave by the designed detection system,then detected and analyzed cardiovascular function.Through the feature point parameters and some basic human body information,the calculation method of relevant cardiovascular parameters was deduced,and the repeatability of the detection system was analyzed.Compared with the standard instrument XY-10 blood flow meter,the correlation coefficient r was greater than 0.9,the correlation was good.The pulse wave signal detection and data processing methods proposed in this thesis provided new techniques for detection,analysis and evaluation for the diagnosis and prevention of cardiovascular disease.