Microphone array apparatus

• US 7,035,416 B2
• Filed: 10/26/2001
• Issued: 04/25/2006
• Est. Priority Date: 06/26/1997
• Status: Expired due to Term

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Matsuo, Naoshi
• Primary Examiner(s): Mei, Xu
• Application Number:
  US10/003,768
• Publication Number:
  US 20020041693A1
• Time in Patent Office: 1,642 Days
• Field of Search: 381/92, 381/91, 381/122, 381/111, 381/113, 381/356, 381/26
• US Class Current: 381/92
• CPC Class Codes: H04R 2201/403 Linear arrays of transducers
• CPC Class Codes: H04R 2410/05 Noise reduction with a separate noise microphone
• CPC Class Codes: H04R 2430/23 Direction finding using a sum-delay beam-former
• CPC Class Codes: H04R 3/005 for combining the signals of two or more microphones specially adapted for hearing aids H04R25/407

Abstract

A microphone array apparatus includes a microphone array including microphones, one of the microphones being a reference microphone, filters receiving output signals of the microphones, and a filter coefficient calculator which receives the output signals of the microphones, a noise and a residual signal obtained by subtracting filtered output signals of the microphones other than the reference microphone from a filtered output signal of the reference microphone and which obtain filter coefficients of the filters in accordance with an evaluation function based on the residual signal.

Claims

1. A microphone array apparatus comprising:

a microphone array including microphones;

a signal estimator which estimates positions of a plurality of estimated microphones in accordance with intervals at which the microphones are arranged by using output signals of the microphones and a velocity of sound and which outputs further output signals of the plurality of estimated microphones estimated to be at the positions together with the output signals of the microphones forming the microphone array; and

a synchronous adder which aligns phases of the output signals of the microphones and the further output signals of the plurality of estimated microphones and then adds the output signals and the further output signals.

2. The microphone array apparatus as claimed in claim 1, further comprising a reference microphone located on an imaginary line connecting the miefephene microphones forming the microphone array and arranged at intervals at which the forming the microphone array are arranged,

wherein the signal estimator corrects the positions of the plurality of estimated microphones and the output signals thereof on a basis of the output signals of the microphones forming the microphone array.

3. The microphone array apparatus as claimed in claim 2, further comprising an estimation coefficient decision unit weights an error signal which corresponds to a difference between the output signal of the reference microphone and the output signals of the signal estimator in accordance with an acoustic sense characteristic so that the signal estimator performs a signal estimation operation on a band having a comparatively high acoustic sense with a comparatively high precision.

4. The microphone array apparatus as claimed in claim 1, wherein;

given angles are defined which indicate directions of a sound source with respect to the microphones forming the microphone array;

a plurality of signal estimators each associated with one of the given angles are provided;

a plurality of synchronous adders each associated with one of the given angles are provided; and

the microphone array apparatus further comprises a sound source position detector which outputs information concerning the position of a sound source based on a maximum value among the output signals of the plurality of the synchronous adders.