title: Noise and disturbance reduction for heart sounds in cycle-frequency domain based on 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.
authors.affiliation: Department of Biomedical Engineering, Dalian University of Technology, Dalian 116024, China. tanghong@dlut.edu.cn
authors.forename: Hong
authors.initials: H
authors.lastname: Tang
authors.forename: Ting
authors.initials: T
authors.lastname: Li
authors.forename: Tianshuang
authors.initials: T
authors.lastname: Qiu
mesh_terms: D000465:Algorithms; D004562:Electrocardiography / Q000379:methods*; D006339:Heart Rate / Q000502:physiology*; D006347:Heart Sounds / Q000502:physiology*; D006801:Humans; D017711:Nonlinear Dynamics; D016011:Normal Distribution; D012815:Signal Processing, Computer-Assisted