An analysis method for wearable electrocardiogram measurement based on non-orthogonal complex wavelet expansion.

An analysis method for wearable electrocardiogram (ECG) measurement is proposed, which is based on the non-orthogonal complex wavelet expansion. The standard continuous wavelet transform performs the signal filtering that corresponds to the orthogonal projection of the ECG signal onto each of the non-orthogonal wavelets. This causes feature leakage from the neighboring wavelet filterbanks and degrades the detection accuracy of the QRS complexes or T waves, even though the wavelets whose waveforms fit to the morphologies of the ECG signals are chosen. The proposed method involves a different signal filtering that corresponds to the non-orthogonal projection of the signal onto each wavelet so that the filter outputs can be the expansion coefficients of the wavelets to approximate the ECG signal. The concept of our proposed method is supported by simulation results.