Robust power line interference suppression for ECG signal based on H∞ filter

The power line interference (PLI) reduction for ECG signals is a challenging task for its time-varying amplitude and time-varying frequency within the spectrum range of ECG signals. Most existing Least Squared-based methods such as Extended Kalman filter to estimate PLI from noisy ECG are vulnerable to the QRS pulses, especially for lower noisy-to-signal ratio ECG. This study proposes a robust tracking method based on H∞ filter to suppress the adverse effect of QRS pulses. The union filter of H∞ and Kalman is also demonstrated in this project. Experiments on ECG records from MIT-BIH arrhythmia database indicate that the H∞ filter and Kalman/H∞ mixed filter are more superior than the Extended Kalman filter in removing the PLI from ECG signal.