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An Optimal Wavelet Based Algorithm for Removal of Power Line Interferences in ECG Signals

Girisha Garg, Shorya Gupta, Vijander Singh, J.R.P. Gupta, A.P.Mittal

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Abstract: An optimal denoising algorithm for ECG signals using Discrete Wavelet Transform is described. Statistical analysis is done to determine the best parameters by comparing different types of wavelet functions, decomposition level and threshold selection methods. The algorithm is used to improve the SNR of the ECG contaminated by disturbances like power line interferences, to present a clean signal for accurate auto diagnosis.


INTRODUCTION


The arrhythmia assessment process from the ECG (electrocardiogram) signals is one of the key steps towards development of completely automatic diagnostic systems. The preliminary requirement of this process is an accurate detection of the ECG beats that corresponds to the R peak of the ECG signal. The ECG is the electrical manifestation of the contractile activity of the heart, and can be recorded fairly easily with surface electrodes on the limbs or chest. Unfortunately, during the recording of the ECG signals the power line interference contaminates the signal. Some of the common causes of the 50 Hz interferences are