臺灣博碩士論文加值系統

生醫電訊號(Biopotential signal)有著極重要的臨床意義，這些生醫訊號均非常的微弱(在mV甚至µV的等級)，在量測時很容易受到干擾，其中，有60(或50)Hz的電源線干擾(Power-line interference)是其中最常見的一種干擾。因為電源線干擾的頻率往往不是永久地固定在同一頻率上，因此可適性濾波器(Adaptive filter)常常用來處理生醫電訊號中的電源線干擾。
可適性濾波器主要是追蹤參考信號的統計特性，根據這些特性的改變，來更正濾波器的參數值，進而得到良好的濾波效果。電源線干擾是以弦波型式出現，在數學模型上容易模擬，歷年來國內外有不少學者都有提出各自改良型的可適性濾波器，但並未有人同時評比各種演算法的可行性以及效能。
在此研究中我們提出了一種遞迴式最小平方(Recursive Least Squares ;RLS)可適性濾波器，具有快速收斂的特性，而且可以濾除電源線干擾中的諧波，同時，我們亦提出數種比較濾波器效能的評估方法，以MIT-BIH資料庫中的心電圖(Electrocardiogram ;ECG)以及自行量測的受電源線干擾的ECG，針對數個不同的可適性濾波器進行比較評估，從各種不同的角度驗證濾波器應用於生醫電訊號干擾濾除之效能及其可行性，進而獲得具有量化的評比標準推薦的可適性濾波演算法。

Biopotential signals are of clinician importance. All of such signals are very tiny (in mV or even in uV range). Biopotential measurements are easily contaminated by power-line interference. As the frequency of the power-line interference is not a fixed one, the adaptive filter is usually used to remove such kind of interference.
Adaptive filter primarily updates its filter parameters by tracking the statistical characteristics of the reference signal, suck that the purposed of interference filtering can be attained. Because the power-line interference can be roughly modeled by a sinusoidal wave, it is easily simulated by mathematical model. Many researches have been devoted to power-line interference removal via adaptive filter, however, no study has been done on the feasibility and performance evaluation of the proposed adaptive filters as applied to remove power-line interference.
In this paper, we propose a recursive least-squares (RLS) adaptive filter, which has been proved to be fast in numerical convergence and be capable of removing high-frequency harmonics in severe power-line interference in electrocardiogram (ECG). We also propose several protocols in time domain and frequency domain such that the filtering evaluation may thus be followed thereafter. The performance comparison among the proposed adaptive filter and our other adaptive filters proposed previously for the same purposed have also been made extensively.

誌謝 i
摘要 ii
Abstract iii
目錄 iv
圖目錄 vi
表目錄 viii
第一章 序論 1
1.1 研究背景 1
1.2研究目的 3
第二章 理論背景 5
2.1 心電圖 5
2.1.1 生理電訊號 5
2.1.2 心電圖 6
2.2可適性濾波器 9
2.2.1 最小均方演算法 10
2.2.2 遞迴式最小平方演算法 12
第三章 研究方法 15
3.1 可適性濾波演算法 15
3.1.1 Ahlstrom and Tompkins’ method 15
3.1.2 Pei and Tseng’s method 17
3.1.3 So’s method 19
3.1.4 Ziarani and Konrad’s method 21
3.1.5 Proposed method 24
3.2 效能評估方法 27
3.2.1 收斂時間與追頻效率 27
3.2.2 演算法運算時間 28
3.3.3 時域與頻域統計量 28
3.3 實驗設計與步驟 30
3.4 系統架構 32
3.4.1 前端放大器 32
3.4.2 感測器規格 35
3.4.3 硬體參數設定 36
第四章 實驗結果與分析 40
4.1 收斂時間與追頻效率 40
4.2 運算時間 43
4.3 時域與頻域統計量 43
第五章 結論與討論 59
5.1 結論 59
5.2 討論 63
參考文獻 65
附錄A 67
附錄B 68

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Liu, Y. L., Lin, D. L., Lin, Y. D., “Spice Model for Computer-Aided Design of Biopotential Amplifier,” Biomed. Eng. Appl. Basos Comm., Vol. 16, No. 3, pp.151-156, June 2004.

Lyons, R., and Bell, A., “The Swiss Army Knife of Digital Networks”, IEEE Signal Processing Magazine, pp.90-100, May 2004.

Metting van Rijn, A. C., Peper, A., and Grimbergen, C. A., “High-quality recording of bioelectric events. Part 1 Interference reduction, theory and practice” Medical and Biological Engineering and Computing, Vol. 28, No. 5, pp. 389-397, September 1990(a)

Metting van Rijn, A. C., Peper, A., and Grimbergen, C. A., “High-quality recording of bioelectric events. Part 2 Low-noise, low-power multichannel amplifier design” Medical and Biological Engineering and Computing, Vol. 29, No. 4, pp. 433-440, 1991(b)

Neuman, M. R., “Biopotential amplifiers” in Medical Instrumentation -- Application and Design, 1998, Third Edition, J. G. Webster ED., Houghton Mifflin

Pei, S. C., and Tseng, C. C., “Adaptive IIR Notch Filter Based on Least Mean p-Power Error Criterion” IEEE Transactions on Circuits and Systems-II: Analog and Digital Signal Processing, Vol. 41, No. 8, pp. 525-528, August 1993.

Rangayyan, R. M., Biomedical Signal Analysis: A Case-Study Approach, John Wiley and Sons, 2001.

So, H. C., “Adaptive algorithm for sinusoidal interference cancellation,” Electron. Lett., Vol. 33, No. 22,pp. 1910-1912. Oct. 1997.

Ziarani, A. K., and Konrad, A., “A Nonlinear Adaptive Method of Elimination of Power Line Interference in ECG Signals,” IEEE Transactions on Biomedical Engineering, Vol. 49, No.6,pp. 540-547, June 2002.

網路參考資料

http://www.physionet.org/physiobank/ PhysioBank, November 2006.