A VMD-SWT based ECG denoising technique

During its acquisition phase an ECG signal gets adulterated with distinct variants of undesirable noise thereby degrading its qualitative nature thereby inflicting a restraint on its clinical applicability. Hence it becomes imperative to design efficient methods to remove these artifacts specifically without deteriorating the signal quality. From classical approaches to modern digital methods, a multitude of methods have been reported in the literature for this purpose. In this paper, we have employed a computer-based hybrid approach that scrutinizes the denoising potential of VMD method. It proceeds by disintegrating an ECG signal polluted with high frequency PLI and low frequency noise into a band of VMFs with PLI distributed over lower order modes while as the low frequency noise distributed over the higher order modes. The higher order modes are then separately fed to an SWT system while as the sum of the lower order modes is fed to a non-local mean filter. Finally, the signal is reconstructed from the processed modes to generate a pure ECG signal free from artefacts. The prowess of the given method has been experimentally validated through the improvements in the three empirical parameters viz.: output SNR, cross-correlation coefficient and percentage root-mean-square difference. These parameters ascertain that the ECG signal has been efficiently denoised and faithfully reconstructed whilst maintaining and preserving its overall features. The experiments have been performed on the various recordings available online at MIT-BIH arrhythmia database.