Design and Evaluation of Nonuniform DFT Filter Banks in Subband Microphone Arrays

Document type: Conference Papers
Peer reviewed: Yes
Full text:
Author(s): Jan Mark de Haan, Nedelko Grbic, Ingvar Claesson, Sven Nordholm
Title: Design and Evaluation of Nonuniform DFT Filter Banks in Subband Microphone Arrays
Conference name: ICASSP (International Conference on Acoustics, Speech and Signal Processing)
Year: 2002
Pagination: II-1173-6 vol.2
ISBN: 0-7803-7402-9
Publisher: IEEE
ISI number: 000177510400294
Organization: Blekinge Institute of Technology
Department: Department of Telecommunications and Signal Processing (Institutionen för telekommunikation och signalbehandling)
Department of Telecommunications and Signal Processing S-372 25 Ronneby
+46 455 38 50 00
Authors e-mail: jmd@bth.se
Language: English
Abstract: This paper presents a method for the design of nonuniform DFT filter banks for subband beamforming. Filter banks designed with the method are evaluated in subband beamforming in a real-world microphone array application. Different source positions in array applications give rise to different signal delays, which means that adaptive beamformers in the subbands alter the phase information of the subband signals in order to extract the source from a noisy background. Phase alterations in the subbands lead to signal degradations when perfect reconstruction filter banks are used for the subband decomposition and reconstruction. The objective of the proposed design is to minimize the magnitude of all aliasing components individually, such that aliasing distortion is minimized although phase alterations occur in the subbands. The proposed method is evaluated in a car hands-free mobile telephony environment with real speech signals and the results show that the performance can be increased by several decibel when using nonuniform filter banks instead of uniform filterbanks while maintaining the length of the subband filters.
Subject: Signal Processing\Beamforming
Keywords: Speech Enhancement, Filter Bank Design
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