Silencing apparatus

• US 5,548,652 A
• Filed: 11/12/1992
• Issued: 08/20/1996
• Est. Priority Date: 03/11/1992
• Status: Expired due to Term

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Electric Corporation
• Inventors: Fujiwara, Susumu, Sakata, Masahiko, Ishizuka, Mikio
• Primary Examiner(s): Kuntz, Curtis
• Assistant Examiner(s): LEE, PING
• Application Number:
  US07/974,976
• Time in Patent Office: 1,377 Days
• Field of Search: 381/71, 381/94, 381/86
• US Class Current: 381/71.6
• CPC Class Codes: G10K 11/17823 Reference signals, e.g. ambient acoustic environment
• CPC Class Codes: G10K 11/1783 handling or detecting of non-standard events or conditions, e.g. changing operating modes under specific operating conditions
• CPC Class Codes: G10K 11/17854 the filter being an adaptive filter
• CPC Class Codes: G10K 11/17857 Geometric disposition, e.g. placement of microphones
• CPC Class Codes: G10K 11/17881 the reference signal being an acoustic signal, e.g. recorded with a microphone
• CPC Class Codes: G10K 2210/103 Three dimensional
• CPC Class Codes: G10K 2210/1081 Earphones, e.g. for telephones, ear protectors or headsets
• CPC Class Codes: G10K 2210/1283 Trains, trams or the like
• CPC Class Codes: G10K 2210/3033 Information contained in memory, e.g. stored signals or transfer functions
• CPC Class Codes: G10K 2210/3039 Nonlinear, e.g. clipping, numerical truncation, thresholding or variable input and output gain
• CPC Class Codes: G10K 2210/3046 Multiple acoustic inputs, multiple acoustic outputs
• CPC Class Codes: H04M 1/19 Arrangements of transmitters, receivers, or complete sets to prevent eavesdropping, to attenuate local noise or to prevent undesired transmission; Mouthpieces or receivers specially adapted therefor circuit arrangements for preventing eavesdropping H04M1/68; telephone cabinets E04H1/14

Abstract

A silencing apparatus for effectively reducing noises in the three dimension space which detects physical characteristics of the noise source by the laser doppler sensor unit during the noise source comes close to the telephone booth, and collects acoustic characteristics of the noise source by the sensor microphone array. The control portion generates an inverse-phased signal against the noise source so that the noises are decreased at the error sensor, and stores the noise source information (physical characteristics and the acoustic characteristics) and the generated inverse-phased signal. When the same noise source come closely, the voice is generated from the speaker using the inverse-phased signal stored in the memory. The control potion generates an inverse-phased voice from the speaker when the collected noise by the sensor microphone is actually over a certain threshold level.

Claims

1. A silencing apparatus comprising:

microphone sensor arrays for measuring acoustic characteristics of the noise which is generated by an approaching one of a plurality of different noise sources, when said approaching one is moving toward the silencing apparatus;

optical sensor means for detecting physical characteristics of the approaching one of the noise sources as it is moving toward the silencing apparatus;

control means responsive to the optical sensor means for deciding which of a plurality of predetermined noise source types the approaching one of the noise sources belongs to, according to the physical characteristics detected by the optical sensor means; and

noise reduction means responsive to the microphone sensor arrays, to the optical sensor means, and to the control means, for outputting a noise reduction signal which reduces the noise according to the type of the noise source as determined by the control means according to the characteristics of the noise source detected by said optical sensor means.

2. A silencing apparatus according to claim 1, wherein said optical sensor means comprise a laser doppler sensor for detecting the physical characteristics of the approaching one of the noise sources.

3. A silencing apparatus according to claim 1, wherein said noise reduction means reduce the noise within a predetermined space in accordance with the acoustic characteristics and the physical characteristics of the approaching one of the noise sources.

4. A silencing apparatus according to claim 1, wherein said noise reduction means comprises:

memory means for storing at least one stored noise reduction signal in advance corresponding to at least one of the predetermined noise source types; and

noise reduction signal generating means for generating a noise reduction signal corresponding to one of the at least one stored noise reduction signal retrieved from the memory means in response to a decision by the control means according to the physical characteristics of the approaching one of the noise sources detected by said optical sensor means.

5. A silencing apparatus according to claim 1, wherein a portion of the noise reaches the apparatus, and further comprising a delay circuit which delays the noise reduction signal for a predetermined time according to the duration of the noise travelling from the approaching one of the noise sources to the apparatus.

6. The apparatus of claim 1 wherein the physical characteristics detected by the optical sensor means include a speed of the approaching one of the noise sources.

7. The apparatus of claim 1 wherein the physical characteristics detected by the optical sensor means include a length of the approaching one of the noise sources.

8. The silencing apparatus of claim 1 wherein the plurality of noise source types includes an unknown noise source type.

9. A silencing apparatus comprising:

microphone sensor arrays for measuring acoustic characteristics of the noise which is generated by an approaching one of a plurality of different noise sources, when said approaching one is moving toward the silencing apparatus;

an optical sensor for detecting physical characteristics of the approaching one of the noise sources as it is moving toward the silencing apparatus;

a controller responsive to the optical sensor for deciding which of a plurality of predetermined noise source types the approaching one of the noise sources belongs to, according to the physical characteristics detected by the optical sensor; and

a noise reduction signal generator responsive to the microphone sensor arrays, to the optical sensor, and to the controller, for outputting a noise reduction signal which reduces the noise according to the type of the noise source as determined by the controller according to the characteristics of the noise source detected by said optical sensor.

10. A silencing apparatus according to claim 9, wherein said optical sensor comprises a laser doppler sensor unit for detecting the physical characteristics of the approaching one of the noise sources.

11. A silencing apparatus according to claim 9, wherein said noise reduction signal generator is for reducing the noise within a predetermined space in accordance with the acoustic characteristics and the physical characteristics of the approaching one of the noise sources.

12. A silencing apparatus according to claim 9, wherein said noise reduction signal generator comprises:

memory for storing at least one stored noise reduction signal in advance corresponding to at least one of the predetermined noise source types; and

noise reduction signal generating apparatus for generating a noise reduction signal corresponding to one of the at least one stored noise reduction signal retrieved from the memory in response to a decision by the controller according to the physical characteristics of the approaching one of the noise sources detected by said optical sensor.

13. A silencing apparatus according to claim 9, further comprising a delay circuit which delays the noise reduction signal for a predetermined time according to the duration of the noise travelling from the approaching one of the noise sources to the apparatus.

14. The apparatus of claim 9 wherein the physical characteristics detected by the optical sensor include a speed of the approaching one of the noise sources.

15. The apparatus of claim 9 wherein the physical characteristics detected by the optical sensor include a length of the approaching one of the noise sources.

16. The silencing apparatus of claim 9 wherein the plurality of noise source types includes an unknown noise source type.

17. A silencing apparatus, comprising:

a sensor for detecting physical characteristics of a vehicle that is sufficiently close to a telephone that noise produced by the vehicle is loud enough to be heard at the telephone;

a controller responsive to the sensor for deciding which of a plurality of predetermined vehicle types the vehicle belongs to, according to the physical characteristics detected by the sensor;

a noise reduction signal generator responsive to said sensor and to said controller for providing a noise reduction signal which reduces the noise produced by the vehicle at the telephone according to the type of the vehicle as determined by the controller according to the characteristics of the vehicle detected by said sensor; and

wherein said sensor comprises an optical sensor and said optical sensor comprises a doppler laser unit that detects the passing time, the speed and the length of said vehicle.

18. A silencing apparatus, comprising:

a sensor for detecting physical characteristics of a vehicle that is sufficiently close to a telephone that noise produced by the vehicle is loud enough to be heard at the telephone;

a controller responsive to the sensor for deciding which of a plurality of predetermined vehicle types the vehicle belongs to, according to the physical characteristics detected by the sensor;

a noise reduction signal generator responsive to said sensor and to said controller for providing a noise reduction signal which reduces the noise produced by the vehicle at the telephone according to the type of the vehicle as determined by the controller according to the characteristics of the vehicle detected by said sensor;

further including an acoustic sensor for measuring acoustic characteristics of the vehicle, and wherein said noise reduction signal generator reduces the noise produced by the vehicle according to the acoustic characteristics measured by said acoustic sensor; and

further including a noise sensor placed proximate to the telephone for measuring ambient noises proximate the telephone, and wherein said noise reduction signal generator reduces the noise produced by the vehicle according to the measured ambient noises measured by said noise sensor.

19. A silencing apparatus, comprising:

a sensor for detecting the presence of a vehicle that is sufficiently close to a telephone that noise produced by the vehicle is loud enough to be heard at the telephone,

a noise reduction signal generator responsive to said sensor for providing a noise reduction signal which reduces the noise produced at the telephone by the vehicle if the presence of the vehicle is detected by said sensor,

control circuitry for selectively activating and deactivating said noise reduction signal generator according to the noise measured by a noise sensor, wherein deactivating said noise reduction signal generator causes said noise reduction signal generator to cease generating any noise reduction signals, and

wherein said sensor comprises an optical sensor and wherein said optical sensor comprises a doppler laser unit that detects the passing time, the speed and the length of said vehicle.

20. A silencing apparatus, comprising:

a sensor for detecting the presence of a vehicle that is sufficiently close to a telephone that noise produced by the vehicle is loud enough to be heard at the telephone,

a noise reduction signal generator responsive to said sensor for providing a noise reduction signal which reduces the noise produced at the telephone by the vehicle if the presence of the vehicle is detected by said sensor,

control circuitry for selectively activating and deactivating said noise reduction signal generator according to the noise measured by a noise sensor, wherein deactivating said noise reduction signal generator causes said noise reduction signal generator to cease generating any noise reduction signals,

further including an acoustic sensor for measuring acoustic characteristics of the vehicle, and wherein said noise reduction signal generator reduces the noise produced by the vehicle according to the acoustic characteristics measured by said acoustic sensor, and

further including a second noise sensor placed proximate to the telephone for measuring ambient noises proximate the telephone, and wherein said noise reduction signal generator reduces the noise produced by the vehicle according to the measured ambient noses measured by said second sensor.

21. A silencing apparatus, comprising:

a sensor for detecting physical characteristics of a vehicle that is sufficiently close to a telephone that noise produced by the vehicle can be heard at the telephone;

a controller responsive to the sensor for deciding which of a plurality of predetermined vehicle types the vehicle belongs to, according to the physical characteristics detected by the sensor;

a noise reduction signal generator responsive to said sensor and to said controller for providing a noise reduction signal which reduces the noise produced by the vehicle at the telephone according to the type of the vehicle as determined by the controller according to the characteristics of the vehicle detected by said sensor; and

wherein the physical characteristics detected by the sensor include a length of the vehicle.

22. A silencing method, comprising:

measuring acoustic characteristics of noise which is generated by an approaching one of a plurality of different noise sources when said approaching one is moving toward the silencing apparatus;

detecting physical characteristics of the approaching one of the noise sources as it is moving toward the silencing apparatus;

deciding which of a plurality of predetermined noise source types the one of the noise sources belongs to, according to the physical characteristics detected by the step of detecting;

providing a noise reduction signal which reduces noises according to the type of the noise source as determined by the step of deciding and according to the step of measuring; and

wherein the step of detecting physical characteristics of the approaching one of the noise sources includes detecting a length of the approaching one of the noise sources.