Research On Monitoring System Based On Contactless BCG

The design and technology mentioned in this thesis can easily obtain important heart rate parameters and cardiovascular disease related parameters,promoting BCG family monitoring and helping to understand our basic physiological health.Nowadays,due to the rapidly growing demand for cheap medical and health care equipment,coupled with the sharp increase in the number of the elderly and the population with cardiovascular diseases,the main objective of this study is to find a simple,novel and low-cost solution so as to monitor heart rate and cardiovascular related parameters in the family without barrier.It is hoped that this solution can be applied to families of healthy or sick people to improve their quality of life.The main work is as follows:(1)A new method for estimating heart rate from BCG signal is established,which solves the problem of insufficient heart rate extraction from traditional BCG.Firstly,weak cardiac activity signals are collected in real time by embedded sensors,and the signals are filtered and converted to obtain local BCG beats.Then,the heart rate is directly estimated from BCG beats without using heartbeat templates.This may provide a new method to estimate heart rate for hospital clinic and home care.(2)It provides ideas for BCG in the diagnosis and analysis of cardiovascular diseases.The BCG waveforms of normal testees and testees suffering from cardiovascular diseases were simply analyzed.The test results show that there are significant differences between normal BCG and abnormal BCG,and these differences may become a tool for diagnosis or prevention of cardiovascular diseases.(3)In order to achieve a non-contact measurement method,this study used a strain gauge embedded in the bottom of the mattress to obtain BCG data.According to the characteristics of the sensor,a lock-in BCG amplifier circuit is designed to ensure that the collected signal will not produce distortion.The flicker noise area of the input stage can be bypassed by exciting the strain gauge with square wave and synchronously demodulating the differential bridge output.This method will reduce the background noise of the system by 7.7 d B.