Optimal and Adaptive Microphone Arrays for Speech Input in Automobiles

  • Sven Nordholm
  • Ingvar Claesson
  • Nedelko Grbić
Part of the Digital Signal Processing book series (DIGSIGNAL)

Abstract

In this chapter, speech enhancement and echo cancellation for hands-free mobile telephony are discussed. A number of microphone array methods have been tested and results from car measurements are given. Traditional methods such as linearly constrained beamforming and generalized sidelobe cancelers are discussed as well as array gain optimization methods. An in situ calibrated method which gives an overall improved performance is also presented. Algorithms such as Least-Squares (LS) and Normalized-Least-Mean-Squares (NLMS) are used to find optimal weights. Improved performance using an LS-method is shown, but at the cost of increased numerical complexity limiting its implementation in real-time applications. By introducing subband processing this issue can be avoided. The results show a noise suppression of approximately 18 dB and hands-free loudspeaker suppression of the same order.

Keywords

Attenuation Convolution Cross Correlation Deconvolution Acoustics 

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Copyright information

© Springer-Verlag Berlin Heidelberg 2001

Authors and Affiliations

  • Sven Nordholm
    • 1
  • Ingvar Claesson
    • 2
  • Nedelko Grbić
    • 2
  1. 1.Curtin University of TechnologyPerthAustralia
  2. 2.Blekinge Institute of TechnologyRonnebySweden

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