title: Frequency-domain beamformers using conjugate gradient techniques for speech enhancement.
abstract: A multiple-iteration constrained conjugate gradient (MICCG) algorithm and a single-iteration constrained conjugate gradient (SICCG) algorithm are proposed to realize the widely used frequency-domain minimum-variance-distortionless-response (MVDR) beamformers and the resulting algorithms are applied to speech enhancement. The algorithms are derived based on the Lagrange method and the conjugate gradient techniques. The implementations of the algorithms avoid any form of explicit or implicit autocorrelation matrix inversion. Theoretical analysis establishes formal convergence of the algorithms. Specifically, the MICCG algorithm is developed based on a block adaptation approach and it generates a finite sequence of estimates that converge to the MVDR solution. For limited data records, the estimates of the MICCG algorithm are better than the conventional estimators and equivalent to the auxiliary vector algorithms. The SICCG algorithm is developed based on a continuous adaptation approach with a sample-by-sample updating procedure and the estimates asymptotically converge to the MVDR solution. An illustrative example using synthetic data from a uniform linear array is studied and an evaluation on real data recorded by an acoustic vector sensor array is demonstrated. Performance of the MICCG algorithm and the SICCG algorithm are compared with the state-of-the-art approaches.
authors.affiliation: Advanced Digital Sciences Center (ADSC), 1 Fusionopolis Way, #08-10 Connexis North Tower, Singapore 138632, Singapore.
authors.forename: Shengkui
authors.initials: S
authors.lastname: Zhao
authors.affiliation: Coordinated Science Laboratory, University of Illinois at Urbana-Champaign, 1308 West Main Street, Urbana, Ilinois 61801.
authors.forename: Douglas L
authors.initials: DL
authors.lastname: Jones
authors.affiliation: School of Engineering, Deakin University, 1 Gheringhap Street, Geelong, Victoria 3220, Australia.
authors.forename: Suiyang
authors.initials: S
authors.lastname: Khoo
authors.affiliation: Faculty of Engineering & Industrial Sciences (H38), Swinburne University of Technology, P.O. Box 218 Hawthorn, Victoria 3122, Australia.
authors.forename: Zhihong
authors.initials: Z
authors.lastname: Man