A Rapid Analysis Method of Human Skin Surface Impedance for Real-time ECG Signal Recovery

• Main Authors: Cheng, Chun-Lin, 鄭椿霖
• Other Authors: Yu, Hsing-Cheng
• Format: Others
• Language: zh-TW
• Published: 2017
• Online Access: http://ndltd.ncl.edu.tw/handle/a99afa

碩士 === 國立臺灣海洋大學 === 系統工程暨造船學系 === 105 === In recent years, many physiological sensing devices have been developed to monitor human health. The electrocardiography (ECG) signal observation is the most public method to determine human health directly and quickly; however, the acquired ECG signal is susceptible to interference. Hence, there is only heart rate measurement in wearable products presently. In order to enhance the characteristics of the ECG signals and to determine human health accurately, a rapid analysis method of human skin surface impedance for real-time ECG signal recovery was presented in this study. The equivalent circuit model of the human skin surface impedance could be extracted by three-point frequency measurement quickly. Three common electrodes were utilized to measure the human skin surface impedance and acquire the ECG signals. The human skin surface impedance of a wet electrode is not susceptible to interference by body movement because it has a well contact between the human skin surface and the electrode. However, it is only suitable to apply in medical and academic field because of its inconvenience for using. The human skin surface impedances of smart suits have better response of body movement and stable measurement because of conductive textile electrode design. The change rates of the impedance at 0 Hz (DC), 100 Hz, and 200 Hz could be achieved 27.0%, 38.5%, and 60.8%, respectively. The change rate of equivalent circuit model parameters of Rs, Rd, and Cd could reach to 94.3%, 24.4%, and -11.5%, respectively, i.e. it is more favorable to determine the ECG signals. The human skin surface impedance spectrum could be extracted by the equivalent circuit model parameters, and the ECG signal recovery could be obtained by fast Fourier transform (FFT). According to the wet electrode, the R, S, and T waves could be amplified on 6.7%, 6.7%, 7.1%, respectively. For the heart rate belt, the R, S, and T waves could be enlarged upon 7.0%, 6.4%, 10.3%, respectively. The R, S, and T waves regarding the smart suits could be magnified 8.1%, 7.8%, 10.6%, respectively.