This paper proposes a near-field broadband adaptive beamforming scheme for intelligent computer telephony and teleconferencing applications, namely the nested microphone array with adaptive noise canceller (NMA-ANC). The NMA-ANC scheme incorporates an harmonically nested array with a nonuniformly subbanded multirate filter bank. Each subband array employs several near-field delay-filter-and-sum beamformers and an adaptive noise canceller (ANC). The proposed NMA-ANC is evaluated via a noise rejection experiment and dereverberation experiment performed in an anechoic chamber and a real conference room, respectively. The experiment data are recorded by a multichannel digital recording system developed using commercial off-the-shelf (COTS) equipments. A perceptual analysis/measurement system (PAMS) test is also carried out using a COTS digital speech level analyzer. The results of the experimental evaluation and PAMS test show that the proposed NMA-ANC scheme is able to improve the sound quality by adaptively rejecting multiple interfering signals and attenuating the reverberant noises and avoiding the desired signal cancellation.


Electrical and Computer Engineering

Keywords and Phrases

Adaptive Noise Canceller; COTS Digital Speech Level Analyzer; COTS Equipments; NMA; PAMS Test; Acoustic Transducer Arrays; Adaptive Noise Cancellers; Anechoic Chamber; Array Signal Processing; Broadband Beamforming; Channel Bank Filters; Commercial Off-The-Shelf; Conference Room; Dereverberation; Dereverberation Experiment; Desired Signal Cancellation; Harmonically Nested Array; Intelligent Computer Telephony; Interference Rejection; Interference Suppression; Microphones; Multichannel Digital Recording; Multichannel Digital Recording System; Multiple Interfering Signal Rejection; Near-Field Beamforming; Near-Field Broadband Adaptive Beamforming Scheme; Near-Field Delay-Filter-And-Sum Beamformers; Nested Microphone Array; Noise Rejection Experiment; Nonuniformly Subbanded Multirate Filter Bank; Perceptual Analysis Measurement System; Reverberant Noise Attenuation; Sound Quality Improvement; Subband Multirate Systems; Teleconferencing; Teleconferencing Applications; Telephony

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Article - Journal

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Final Version

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© 2004 Institute of Electrical and Electronics Engineers (IEEE), All rights reserved.

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