Design Of Heart Sound Detection System

In recent years,the problems caused by residents’ bad living habits have become increasingly prominent,and the impact of cardiovascular disease on the health of residents has become more and more significant,meanwhile,the incidence of cardiovascular disease has continued to increase.With the development of electronic technology,relevant research on the heart sound detection system is also progressed gradually.Heart sound is a weak signal of the human body,therefore,in view of the problem that traditional stethoscopes are easily interfered by environmental factors and lack of precision,new requirements are put forward for the performance of the heart sound detection system.This subject has designed a set of heart sound detection system through the following work,which include as follows:Research on the heart sound signal generation mechanism,physiological significance and noise that interfered with heart sound are analyzed and processed.In addition,the detection system,which mainly includes the construction of hardware acquisition circuit,the design of mobile software,as well as the research of heart sound denoising algorithm,as well as the recognition of the first heart sound and the second heart sound are also designed.Firstly,the hardware circuit and software functional modules of the heart sound detection system are designed to verify the detection effect of the heart sound signal.As to the noise problem of the heart sound signal processed by the hardware circuit,the wavelet threshold function is used to denoise the digital filter processing in the follow-up.Aiming at the defects of the traditional threshold function such as excessive noise reduction and discontinuity,the wavelet threshold function is improved,the adjustment factor is introduced,the optimal threshold and wavelet base are selected,so that signal-to-noise ratio is up to 43.43 db after the advanced threshold function is finished.The Mel Cepstrum algorithm is used for the processed heart sound signal to locate and eliminate the friction sound caused by the position changes of the auscultation head.Secondly the heart sound signal is analyzed in time domain and frequency domain to extract the first heart sound and the second heart sound,and the detection rate of the first heart sound and the second heart sound of the normal heart sound reaches 95.4%.Finally,the real-time auscultation,audio preservation,waveform display and intelligent analysis of heart sounds are realized through the software design of the mobile terminal,so as to make the design of the heart sound detection system completed.