Research Of Collection And Analysis On Heart Sounds

Heart sound signal is one of the most important physiological signals. Heart sounds auscultation is an important way of non-invasive examination of heart diseases. Regardless of the latest advances in ECG techniques, heart sound auscultation is still the first choice being done in cardiac clinic. But stethoscope has been used to carry out auscultation process. Traditional stethoscope, however, has several drawbacks, which holds back the development of heart sound auscultation. Phonocardiograms (PCGs) visualize cardiac auscultation, and improve the diagnosis level if cardiovascular diseases. It is convenient to analyze the heart sound and extract the characteristic parameter for doctors to obtain basic information of heart and make more exact diagnosis. Up to now, the system of heart sounds collecting and analyzing method is still quite immature. No electronic equipment has been applied in clinic.The paper has designed a kind of potable heart sound analyzing instrument based on embedded computer and has achieved the following functions: acquit heart sounds, capture and display current heart sound signals; manage patient information and data files, perform the spectrum and time analysis of the heart sounds; replay the shape and sound of heart sound signals, and review the previous recordings. The instrument is small, low-cost and convenient to operate. This study provides some basic analysis methods and the analysis tool for clinic. And it also plays a basis role for the assistant diagnosis of the heart diseases. The heart sound signal is non-stationary. In order to get a comprehensive understanding of the characteristic for the heart sound, it is necessary to analyze it in time, frequency, and time-frequency domain. Due to the interference, the heart sound signal is nosed so that the preprocessing is necessary to remove the noises.After the preprocessing, the quality of signal is improved and can be used for further analysis.The main works in this paper are listed as follows:(1) Study on the basic knowledge of heart sounds, consists of the mechanism of production and key property of heart sounds;(2) Analyzed the noises of heart sound collection and the characteristic of heart sound sensors, and designed a heart sounds sensor.(3) Design the analog signal processing circuit, digital processing circuit and the methods of signal processing. (4)Based the Matlab, the paper designed a filter and analyzed the heart sound in time, frequency, time-frequency domain, extracted the envelope of the heart sound.(5)To operate heart sound analysis system conveniently, the paper programmed a control system in C++, the system is designed with control modules and the function is implemented with callback functions.Finally,we made a conclusion , point out some disadvantages of the system, also propose the future research directions in this field.