Reduced-order robust superdirective beamforming with uniform linear microphone arrays

Chao Pan, Jingdong Chen, Jacob Benesty

Research output: Contribution to journalArticlepeer-review

9 Scopus citations

Abstract

Sensor arrays for audio and speech signal acquisition are generally required to have frequency-invariant beampatterns to avoid adding spectral distortion to the broadband signals of interest. One way to obtain frequency-invariant beampatterns is via superdirective beamforming. However, traditional superdirective beamformers may cause significant white noise amplification (particularly at lowfrequencies), making them sensitive to uncorrelated white noise. To circumvent the problem of white noise amplification, a method was developed to find the superdirective beamforming filter with a constraint on the white noise gain (WNG), leading to the so-called WNG-constrained superdirective beamformer. But this method damages the frequency invariance of the beampattern. In this paper, we develop a flatness-constrained robust superdirective beamformer. We divide the overall beamformer into two subbeamformers, which are convolved together: one subbeamformer forms a lower order superdirective beampattern while the other attempts to improve the WNG. We show that this robust approach can improve theWNG while limiting the frequency dependency of the beampattern at the same time.

Original languageEnglish
Pages (from-to)1548-1559
Number of pages12
JournalIEEE/ACM Transactions on Audio Speech and Language Processing
Volume24
Issue number9
DOIs
StatePublished - 1 Sep 2016

Keywords

  • Beampattern design
  • cardioid
  • directivity factor
  • microphone arrays
  • robust beamforming
  • superdirective beamforming
  • white noise gain

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