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.

Adaptive noise canceller, Broadband beamforming, Dereverberation, Interface rejection, Multichannel digital recording, Near-field beamforming, Nested microphone array (NMA), Subband multirate systems
IEEE Transactions on Instrumentation and Measurement
Department of Systems and Computer Engineering

Zheng, Y.R. (Yahong R.), Goubran, R, & El-Tanany, M. (2004). Experimental evaluation of a nested microphone array with adaptive noise cancellers. IEEE Transactions on Instrumentation and Measurement, 53(3), 777–786. doi:10.1109/TIM.2004.827304