| Summary: | 碩士 === 國立臺灣師範大學 === 機電科技研究所 === 100 === In the diagnosis of the respiratory diseases, auscultation is a main method to diagnose and treat patients. Auscultation is a non-invasive and convenient diagnostic method. With the upgrading of computer hardware, Digital auscultation is gradually replacing traditional auscultation. Auscultation digitizing overcomes the shortcomings that are not sensitive and the subjectivity of the human’s ear. And auscultation also has the advantages that are multi-tasking, recordable and can be analyzed by computer. We can know a lot of information by image-based of lung sound signals. In the digital auscultation analysis, what method I use to analyze the lung signals which microphone recorded will affect the results of the experiment greatly. The purpose of this study is to build a system to observe the lung sounds of the different athletes by combination of lung sound recording system and time-frequency analysis. And find the lung sound characteristics and relationships of different athletes from the results.
First, I combine the stethoscopes and unidirectional microphones (Audio-Technica AT9904) as 16 digital stethoscopes, and arrange the digital stethoscope array on the back of human’s body. Through the USB sound cards and Audio Stream Input Output(ASIO) driver, the lung sound signals are recorded and saved in the hard disk. The signal would be processed and analyzed by MATLAB and Visual signal. The research has used three time-frequency analysis methods, they are Short Time Fourier Transform (STFT), Morlet Wavelet transform (Morlet WT) and Hilbert Huang transform (HHT). This research considers the result of HHT is the most suitable for lung sound signals analysis. Entropy is also used for respiratory air flow detection. This research build a system to observe the characterizes of lung sound signals from different athletes by the above method
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