title: Wavelet-based unsupervised learning method for electrocardiogram suppression in surface electromyograms.
abstract: We present a novel approach aimed at removing electrocardiogram (ECG) perturbation from single-channel surface electromyogram (EMG) recordings by means of unsupervised learning of wavelet-based intensity images. The general idea is to combine the suitability of certain wavelet decomposition bases which provide sparse electrocardiogram time-frequency representations, with the capacity of non-negative matrix factorization (NMF) for extracting patterns from images. In order to overcome convergence problems which often arise in NMF-related applications, we design a novel robust initialization strategy which ensures proper signal decomposition in a wide range of ECG contamination levels. Moreover, the method can be readily used because no a priori knowledge or parameter adjustment is needed. The proposed method was evaluated on real surface EMG signals against two state-of-the-art unsupervised learning algorithms and a singular spectrum analysis based method. The results, expressed in terms of high-to-low energy ratio, normalized median frequency, spectral power difference and normalized average rectified value, suggest that the proposed method enables better ECG-EMG separation quality than the reference methods.
authors.affiliation: Deptartment Ingeniería Eléctrica y Electrónica, Universidad Pública de Navarra Campus Arrosadía, 31006 Pamplona, Spain. Electronic address: maciej.niegowski@unavarra.es.
authors.forename: Maciej
authors.initials: M
authors.lastname: Niegowski
authors.affiliation: Deptartment Ingeniería Eléctrica y Electrónica, Universidad Pública de Navarra Campus Arrosadía, 31006 Pamplona, Spain. Electronic address: miro@unavarra.es.
authors.forename: Miroslav
authors.initials: M
authors.lastname: Zivanovic
mesh_terms: D004562:Electrocardiography; D004576:Electromyography; D006801:Humans; D012815:Signal Processing, Computer-Assisted; D000069558:Unsupervised Machine Learning; D058067:Wavelet Analysis
keywords: Electrocardiogram removal; Electromyography; Non-negative matrix factorization; Wavelets