Virtues and Vices of Source Separation Using Linear Independent Component Analysis for Blind Source Separation of Non-Linearly Coupled and Synchronised Fetal and Mother ECGs

Abstract

In this paper, we address the imminent problem which arises when researchers unjudiciously use a linear and instantaneous (memoryless) model for the source mixing structures of independent component analysis (ICA), also known as blind source separation (BSS), in pursuit of separating noisy and frequently non stationary combined mother and fetal electrocardiogram (ECG) signals from cutaneous measurements under the following false assumptions. (1) Sensors (electrodes) are instantaneous linear mixtures of mother and fetal source signals. (2) Noise is an additive Gaussian perturbation. (3) Mother and fetal ECG signals are assumed to be stationary and linear, mutually statistically independent and statistically independent from noise. (4) Most of the second-order (SO) and fourth-order (FO) blind source separation (BSS) methods developed this last decade assume that third-order cumulants vanish hence the need to use FO. All these assumptions are not valid and will be challenged. We will expose these vices without providing any significant contributions for overcoming them. Rather, we provide a framework for investigations which are based on conformal mapping of nonlinear mixtures and novel dynamic nonlinear structures with time-variant memory to cater for quadratic coupling between mother and fetal which is quasi-periodical and the concomitant (quasi) cyclostationarity. Results given here show linear ICA shortfalls in non stationary environment which is precipitated by quadratic coupling between mother and fetal ECGs during events of synchronised QRS complexes and P-waves and account for more than 20% of the 100,000 maternal cardiac cycles obtained from several clinical trials.

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Document Details

Document Type
Technical Report
Publication Date
Oct 25, 2001
Accession Number
ADA410440

Entities

People

  • A. Mclean
  • E. R. Carson
  • K. T. Grattan
  • M. Sabry-rizk
  • W. Zgallai

Organizations

  • City, University of London

Tags

Communities of Interest

  • Materials and Manufacturing Processes

DTIC Thesaurus Topics

  • Acquisition
  • Algorithms
  • Biomedical Engineering
  • Clinical Trials
  • Conformal Mapping
  • Couplings
  • Data Acquisition
  • Electrocardiography
  • Electrodes
  • Engineering
  • Heart
  • Identification
  • Measurement
  • Order Statistics
  • Signal Processing
  • Stationary
  • Universities

Readers

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