Patent ID: 7181026

Claim:
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 (m 1 (n)) upon receiving an acoustic signal; and the directional microphone ( 2 ) being designed to output a second digital signal (m 2 (n)) upon receiving an acoustic signal; an adaptive filtering circuit system ( 7 ) for generating, based on the first digital signal (m 1 (n)) and on the second digital signal (m 2 (n)), a filter output signal (y 1 (n)) corresponding to an acoustic signal from the first direction and for canceling out said filter output signal (y 1 (n)) from the first digital signal (m 1 (n)), so as to generate a first error signal (e 1 (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 (e 1 (n)), the filter output signal (y 1 (n)), and the first digital signal (m 1 (n)), a second error signal (e 2 (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 (e 1 (n)).