Title of Paper:Noise and Disturbance Reduction for Heart Sounds in Cycle-Frequency Domain Based on Nonlinear Time Scaling

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Date of Publication:2010-02-01

Journal:IEEE TRANSACTIONS ON BIOMEDICAL ENGINEERING

Included Journals:PubMed、SCIE、Scopus

Volume:57

Issue:2

Page Number:325-333

ISSN No.:0018-9294

Key Words:Cycle-frequency domain; cyclic stationarity enhancement; disturbance reduction; heart sounds; noise reduction; nonlinear time scaling

Abstract:Through an investigation of various clinical cases, heart sounds are found to be quasi-cyclostationary. Nonlinear time scaling from cycle-to-cycle is proposed to enhance cyclic stationarity, where nonlinear time scaling is approximated by a piecewise linear function. The techniques of cyclostationary signal processing are employed in this paper to reduce noise and disturbance in the cycle-frequency domain. Heart sounds can be theoretically recovered in the presence of additive, zero mean noise, and disturbance (perhaps non-Gaussian, nonstationary, or colored). The experimental tests in various conditions confirm the theoretical results.