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Post-processing scheme for adaptive directional microphone system with noise/interference suppression

  • US 7,181,026 B2
  • Filed: 08/13/2001
  • Issued: 02/20/2007
  • Est. Priority Date: 08/13/2001
  • Status: Expired due to Term
First Claim
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1. An adaptive directional microphone system for enhancing an acoustic signal from a second direction and for reducing an acoustic signal from at least a first direction different from the second direction, the system comprising:

  • an omni-directional microphone (1) having a first directivity pattern, therein providing a similar gain for acoustic signals at least from the first direction and from the second direction; and

    a directional microphone (2) having a second directivity pattern, therein providing a higher gain for acoustic signals from the first direction than for acoustic signals from the second direction;

    the omni-directional microphone (1) and the directional microphone (2) being arranged in a closely acoustically-coupled way;

    the omni-directional microphone (1) being designed to output a first digital signal (m1(n)) upon receiving an acoustic signal; and

    the directional microphone (2) being designed to output a second digital signal (m2(n)) upon receiving an acoustic signal;

    an adaptive filtering circuit system (7) for generating, based on the first digital signal (m1(n)) and on the second digital signal (m2(n)), a filter output signal (y1(n)) corresponding to an acoustic signal from the first direction and for canceling out said filter output signal (y1(n)) from the first digital signal (m1(n)), so as to generate a first error signal (e1(n)) corresponding to an acoustic signal in which the acoustic signal from the first direction is reduced; and

    a post-processing filter system (31, 32) for producing, based on the first error signal (e1(n)), the filter output signal (y1(n)), and the first digital signal (m1(n)), a second error signal (e2(n)) corresponding to an acoustic signal in which the acoustic signal from the second direction is enhanced as compared to the acoustic signal related to the first error signal (e1(n)).

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