Development And Implementation Of A Bluetooth Stethoscope And Its Supporting Software

Cardiovascular disease is the number one cause of death worldwide and has caused widespread concern in society.Heart sound auscultation is one of the commonly used clinical diagnostic methods.The analysis and processing of heart sound signals can assist doctors in diagnosis.However,the prevention and treatment of traditional cardiovascular diseases requires regular inspections at hospitals,occupying medical resources,time and labor.Therefore,remote heart sound assisted auscultation has important social value and application prospects.Based on the previous research of the research group,An electronic stethoscope and auxiliary auscultation software,which are suitable for remote auscultation in home and community hospitals,are developed.The main contents include:1)Research and implement a real-time heart rate calculation algorithm based on autocorrelation function.This algorithm use sliding window to intercept heart sound signal frame;use low-pass filter to suppress high-frequency noise;use energy envelope and homomorphic envelope to smooth the signal;use autocorrelation of envelope to extract the periodicity of heart sound signal;use single peak detection method to obtain the period of the autocorrelation function,thereby obtaining the heart rate.2)Analyze various factors that may interfere with heart rate calculation and their effect of influence,including the similarity of the first heart sound and the second heart sound,heart noise,background music,breath sounds,friction sounds,sharp noise,and the like.Then propose solutions to overcome various disturbances,including selection of a suitable sliding window size,low-pass filtering,and limiting peak search scope of the autocorrelation function.3)Design an wireless electronic stethoscope based on CSR8670 Bluetooth chip to realize the collection and transmission of heart sound signals;realize the reception of heart sound signals and real-time calculation of heart rate based on Android application.Performance of the electronic stethoscope,and the effectiveness of the real-time heart rate calculation algorithm based on the autocorrelation function,has been verified.