SPEECH PROCESSING SYSTEM, SPEECH PROCESSING METHOD, SPEECH PROCESSING PROGRAM, VEHICLE INCLUDING SPEECH PROCESSING SYSTEM ON BOARD, AND MICROPHONE PLACING METHOD

• US 20160111109A1
• Filed: 01/16/2014
• Published: 04/21/2016
• Est. Priority Date: 05/23/2013
• Status: Active Grant

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: TSUJIKAWA, Masanori, HANAZAWA, Ken, SUGIYAMA, Akihiko
• Granted Patent: US 9,905,243 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B60R 11/0247 for microphones or earphones
• CPC Class Codes: B60R 2011/0028 Ceiling, e.g. roof rails
• CPC Class Codes: G10L 2021/02166 Microphone arrays; Beamforming
• CPC Class Codes: G10L 21/0216 characterised by the method used for estimating noise
• CPC Class Codes: H04R 2227/001 Adaptation of signal processing in PA systems in dependence of presence of noise
• CPC Class Codes: H04R 2499/13 Acoustic transducers and sound field adaptation in vehicles
• CPC Class Codes: H04R 3/005 for combining the signals of two or more microphones specially adapted for hearing aids H04R25/407

Abstract

A system of this invention is directed to a speech processing system that efficiently performs noise suppression processing for a plurality of noise sources spreading in a lateral direction with respect to a speaker of interest. The speech processing system includes a microphone array including a plurality of microphones, each of which inputs a sound mixture including speech of a speaker of interest and noise from a noise source region including a plurality of noise sources placed in a lateral direction with respect to the speaker of interest, and outputs a mixture signal including a speech signal and a noise signal, the plurality of microphones being arranged such that a difference between respective distances from the plurality of microphones to the speaker of interest becomes different from a difference between respective distances from the plurality of microphones to the noise source region, and a noise suppressor that suppresses the noise based on the mixture signals output from the plurality of microphones.

Claims

1. A speech processing system comprising:

a microphone array including a plurality of microphones, each of which inputs a sound mixture including speech of a speaker of interest and noise from a noise source region including a plurality of noise sources placed in a lateral direction with respect to the speaker of interest, and outputs a mixture signal including a speech signal and a noise signal, said plurality of microphones being arranged such that a difference between respective distances from said plurality of microphones to the speaker of interest becomes different from a difference between respective distances from said plurality of microphones to the noise source region; and

a noise suppressor that suppresses the noise based on the mixture signals output from said plurality of microphones.

2. The speech processing system according to claim 1, wherein said plurality of microphones included in said microphone array are arranged on a line that passes through points acquired by projecting the speaker of interest and a point in the noise source region on a plane on which said microphone array is placed.

3. The speech processing system according to claim 2, wherein said plurality of microphones included in said microphone array are arranged on a line that connects, in a shortest distance, a region and a point acquired by projecting the noise source region and the speaker of interest on the plane on which said microphone array is placed.

4. The speech processing system according to claim 2, wherein said plurality of microphones included in said microphone array are arranged on a line that connects points acquired by projecting a center of the noise source region and the speaker of interest on the plane on which said microphone array is placed.

5. The speech processing system according to claim 2, wherein a placement position of said microphone array in a forward/backward direction and a tilt of a placement plane of said microphone array are adjusted so as to decrease differences between respective distances from noise sources in the noise source region to the plurality of microphones of said microphone array.

6. The speech processing system according to claim 1, wherein said microphone array includes not less than three microphones arranged on a line, and

the speech processing system further comprises a selector that selects, out of the not less than three microphones, microphones to output the mixture signals used by said noise suppressor.

7. The speech processing system according to claim 6, wherein said selector selects, out of the not less than three microphones, microphones to output the mixture signals used by said noise suppressor in accordance with a type of driven noise sources.

8. The speech processing system according to claim 6, wherein said selector selects, out of the not less than three microphones, microphones to output the mixture signals used by said noise suppressor in accordance with a position of the speaker of interest.

9. The speech processing system according to claim 6, wherein said selector selects, out of the not less than three microphones, microphones to output the mixture signals used by said noise suppressor in accordance with a frequency of the noise generated from the noise source region.

10. The speech processing system according to claim 6, wherein said selector selects, out of the not less than three microphones, microphones to output the mixture signals used by said noise suppressor in accordance with a frequency of noise generated from a noise source placed outside the noise source region.

11. The speech processing system according to claim 1, further comprising, in addition to said microphone array, at least two microphones arranged in a direction to make a right angle with a line that passes through the speaker of interest and the noise source region;

and

wherein said selector selects, in accordance with noise from a lateral direction generated from left and right noise sources with respect to the speaker of interest, microphones that are arranged in the direction to make the right angle and output the mixture signals used by said noise suppressor.

12. The speech processing system according to claim 1, wherein an interval between microphones in said microphone array is less than 10 cm and preferably falls within a range of 2 cm to 4 cm.

13. The speech processing system according to claim 1, wherein the speaker of interest, the noise source region, and the microphone array exist in a closed space, and

said microphone array is placed on a ceiling of the closed space.

14. The speech processing system according to claim 13, wherein the closed space is a space in a vehicle,

said microphone array is placed on a ceiling above a sun visor, and

portions of the sun visor overlapping the microphones are processed to pass a sound so as to prevent the sun visor from blocking the sound to the microphones of said microphone array.

16. A vehicle including the speech processing system according to claim 1.

15. A speech processing system comprising:

a first microphone that is placed on a ceiling in a vehicle, inputs a sound mixture including noise and a voice of a passenger of the vehicle, and outputs a first mixture signal;

a second microphone that is placed on the ceiling in the vehicle at a front position in the vehicle with respect to said first microphone, inputs a sound mixture including the noise and the voice of the passenger of the vehicle, and outputs a second mixture signal; and

a noise suppressor that outputs an enhanced speech signal based on the first mixture signal and the second mixture signal.

17. A microphone placing method comprising arranging a plurality of microphones, each of which inputs a sound mixture including speech of a speaker of interest and noise from a noise source region including a plurality of noise sources placed in a lateral direction with respect to the speaker of interest, and outputs a mixture signal including a speech signal and a noise signal, such that a difference between respective distances from the plurality of microphones to the speaker of interest becomes different from a difference between respective distances from the plurality of microphones to the noise source region.

18. A speech processing method comprising:

selecting microphones to output a mixture signal including a speech signal and a noise signal, out of a plurality of microphones, each of which inputs a sound mixture including speech of the speaker of interest and noise from a noise source region including a plurality of noise sources placed in a lateral direction with respect to a speaker of interest, and outputs the mixture signal, the plurality of microphones being arranged such that a difference between respective distances from the plurality of microphones to the speaker of interest becomes different from a difference between respective distances from the plurality of microphones to the noise source region; and

suppressing the noise based on the mixture signals output from the selected microphones.

19. A non-transitory computer readable storage medium storing a speech processing program for causing a computer to execute a method, comprising:

selecting microphones to output a mixture signal including a speech signal and a noise signal, out of a plurality of microphones, each of which inputs a sound mixture including speech of the speaker of interest and noise from a noise source region including a plurality of noise sources placed in a lateral direction with respect to a speaker of interest, and outputs the mixture signal, the plurality of microphones being arranged such that a difference between respective distances from the plurality of microphones to the speaker of interest becomes different from a difference between respective distances from the plurality of microphones to the noise source region; and

suppressing the noise based on the mixture signals output from the selected microphones.