| The heart sound signal,as an important physiology signal,contains a wealth of information that reflects the state of the heart,and has important significance in the diagnosis cardiovascular disease.Auscultation is an economical and simple way to acquire heart sounds and has a wide range of applications in the medical community.With the development of telemedicine,patients can be checked by doctors at home,which will saves patients' a lot of time and effort.So,with describing the characteristics of heart sounds,this article intend to research and develop remote heart sound auscultation system based on Android platform.The main research content includes:1.The development of electronic stethoscope,including the selection of sound-electric sensors,the design of heart sound collection circuit,the design of filter amplifying circuit and the design of USB charging circuit.2.The research and implementation of speech suppression algorithm,which intend to suppress the speech that mixed the signal during recording by wavelet threshold filtering method,this paper first compare the difference of frequency characteristic and power between heard sound and speech,to determine the threshold of wavelet filtering method.Then,establishing the evaluation index and testing the filtering effect.3.The research and implementation of heart rate calculation algorithm,heart rate calculation algorithm based on autocorrelation function.This algorithm uses dead-zone nonlinear processing to improve the accuracy,as well as to be applicable to complex hear sound including the abnormal heart sounds and the loud noise signals.Finally,testing on various heart sound signals and verifying the effectiveness of the algorithm.4.The implementation of application based on the Android platform,which provide functions : analyzing and processing heart sound signal?drawing phonocardiogram?heart sound real-time playback?suppressing speech?real-time heart rate calculation?remote transmission and management of users' information. |
PDF Full Text Request