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Báo cáo hóa học: " An Integrated Real-Time Beamforming and Postfiltering System for Nonstationary Noise Environments"

Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: An Integrated Real-Time Beamforming and Postfiltering System for Nonstationary Noise Environments | EURASIP Journal on Applied Signal Processing 2003 11 1064-1073 2003 Hindawi Publishing Corporation An Integrated Real-Time Beamforming and Postfiltering System for Nonstationary Noise Environments Israel Cohen Department of Electrical Engineering Technion - Israel Institute of Technology Haifa 32000 Israel Email icohen@ee.technion.ac.il Sharon Gannot School of Engineering Bar-Ilan University Ramat-Gan 52900 Israel Email gannot@siglab.technion.ac.il Baruch Berdugo Lamar Signal Processing Ltd. Andrea Electronics Corp. P.O. Box 573 Yokneam Ilit 20692 Israel Email bberdugo@lamar.co.il Received 1 September 2002 and in revised form 6 March 2003 We present a novel approach for real-time multichannel speech enhancement in environments of nonstationary noise and timevarying acoustical transfer functions ATFs . The proposed system integrates adaptive beamforming ATF identification soft signal detection and multichannel postfiltering. The noise canceller branch of the beamformer and the ATF identification are adaptively updated online based on hypothesis test results. The noise canceller is updated only during stationary noise frames and the ATF identification is carried out only when desired source components have been detected. The hypothesis testing is based on the nonstationarity of the signals and the transient power ratio between the beamformer primary output and its reference noise signals. Following the beamforming and the hypothesis testing estimates for the signal presence probability and for the noise power spectral density are derived. Subsequently an optimal spectral gain function that minimizes the mean square error of the log-spectral amplitude LSA is applied. Experimental results demonstrate the usefulness of the proposed system in nonstationary noise environments. Keywords and phrases array signal processing signal detection acoustic noise measurement speech enhancement spectral analysis adaptive signal processing. 1. INTRODUCTION Postfiltering methods for .