Method and system for enhancing regional sensitivity noise discrimination

• US 20070047742A1
• Filed: 08/26/2005
• Published: 03/01/2007
• Est. Priority Date: 08/26/2005
• Status: Abandoned Application

• Current Assignee: Dolby Laboratories Licensing Corporation (Dolby Laboratories Incorporated)
• Original Assignee: Step Communications Corporation
• Inventors: Spicer, Bruce, Taenzer, Jon
• Application Number:
  US11/212,498
• Publication Number:
  US 20070047742A1
• Time in Patent Office: Days
• US Class Current: 381/92
• CPC Class Codes: H04R 1/406 microphones
• CPC Class Codes: H04R 2201/401 2D or 3D arrays of transducers
• CPC Class Codes: H04R 2430/23 Direction finding using a sum-delay beam-former
• CPC Class Codes: H04R 29/006 Microphone matching
• CPC Class Codes: H04R 3/005 for combining the signals of two or more microphones specially adapted for hearing aids H04R25/407

Abstract

Noise discrimination in signals from a plurality of sensors is conducted by enhancing the phase difference in the signals such that off-axis pick-up is suppressed while on-axis pick-up is enhanced. Alternatively, attenuation/expansion are applied to the signals in a phase difference dependent manner, consistent with suppression of off-axis pick-up and on-axis enhancement. Nulls between sensitivity lobes are widened, effectively narrowing the sensitivity lobes and improving directionality and noise discrimination.

Claims

1. A method for enhancing regional sensitivity noise discrimination from first and second pairs of sensors, each sensor generating a sensor input signal representable by an input vector having a magnitude and phase, the method comprising:

applying a first process to the first pair of sensors to obtain a first output corresponding to sensitivity in a first region;

applying a second process to the second pair of sensors to obtain a second output corresponding to sensitivity in a second region; and

combining the first and second outputs,

wherein the first process includes enhancing an input phase difference value corresponding to a phase difference between signals from first and second sensors in the first pair of sensors.

2. The method of claim 1, wherein combining comprises summing.

3. The method of claim 1, wherein combining comprises differencing

4. The method of claim 1, further including applying to at least one of the first and second processes sensitivity matching to accommodate device and/or signal mismatch in the system.

5. The method of claim 4, wherein the sensitivity matching is based on a mathematical mean determination selected from the set of:

arithmetic mean, geometric mean, harmonic mean and, a root-mean-square (rms), determinations.

6. The method of claim 1, wherein the first and second pair of sensors are arranged in a one-dimensional array.

7. The method of claim 1, wherein the first and second pair of sensors are arranged in a two-dimensional array.

8. The method of claim 1, wherein enhancing is conducted for phase difference values other than 0 degrees.

9. The method of claim 1, wherein enhancing is conducted asymmetrically about a selected non-enhancement phase difference angle.

36. The method of claim 1, wherein the first and second pair of sensors are arranged in a three-dimensional array.

10. A method for enhancing regional sensitivity noise discrimination from first and second pairs of sensors, each sensor generating a sensor input signal representable by an input vector having a magnitude and phase, the method comprising:

applying a first process to the first pair of sensors to obtain a first output corresponding to sensitivity in a first region;

applying a second process to the second pair of sensors to obtain a second output corresponding to sensitivity in a second region; and

combining the first and second outputs,

wherein the first process includes attenuating an output vector obtained by combining first and second input vectors corresponding to signals from first and second sensors of the first pair of sensors by an attenuation factor which is a function of a difference in phase between the first and second input vectors.

11. The method of claim 10, wherein combining comprises summing.

12. The method of claim 10, wherein combining comprises differencing

13. The method of claim 10, further including applying to at least one of the first and second processes sensitivity matching to accommodate device and/or signal mismatch in the system.

14. The method of claim 13, wherein the sensitivity matching is based on a mathematical mean determination selected from the set of:

arithmetic mean, geometric mean, harmonic mean and, a root-mean-square (rms), determinations.

15. The method of claim 10, wherein the first and second pair of sensors are arranged in a one-dimensional array.

16. The method of claim 10 wherein the first and second pair of sensors are arranged in a two-dimensional array.

17. The method of claim 10, wherein the first and second pair of sensors are arranged in a three-dimensional array.

18. The method of claim 10, wherein attenuation is conducted for phase difference values other than 0 degrees.

19. The method of claim 10, wherein attenuation is conducted asymmetrically about a selected non-attenuation phase angle difference.

20. A system exhibiting enhanced regional sensitivity noise discrimination, the system comprising:

first and second pairs of sensors, each sensor generating a sensor input signal representable by an input vector having a magnitude and phase; and

at least one circuit adapted to;

apply a first process to the first pair of sensors to obtain a first output corresponding to sensitivity in a first region;

apply a second process to the second pair of sensors to obtain a second output corresponding to sensitivity in a second region; and

combine the first and second outputs,

wherein the first process includes enhancing an input phase difference value corresponding to a phase difference between signals from first and second sensors in the first pair of sensors.

21. The system of claim 20, wherein combining comprises summing.

22. The system of claim 20, wherein combining comprises differencing.

23. The system of claim 20, wherein the at least one circuit is further adapted to apply to at least one of the first and second processes sensitivity matching to accommodate device and/or signal mismatch.

24. The system of claim 23, wherein the sensitivity matching is based on a mathematical mean determination selected from the set of:

arithmetic mean, geometric mean, harmonic mean and, a root-mean-square (rms), determinations.

25. The system of claim 20, wherein the first and second pair of sensors are arranged in a one-dimensional array.

26. The system of claim 20. wherein the first and second pair of sensors are arranged in a two-dimensional array.

27. The system of claim 20, wherein the first and second pair of sensors are arranged in a three-dimensional array.

28. A system exhibiting enhanced regional sensitivity noise discrimination, the system comprising:

first and second pairs of sensors, each sensor generating a sensor input signal representable by an input vector having a magnitude and phase; and

at least one circuit adapted to;

apply a first process to the first pair of sensors to obtain a first output corresponding to sensitivity in a first region;

apply a second process to the second pair of sensors to obtain a second output corresponding to sensitivity in a second region; and

combine the first and second outputs,

wherein the first process includes attenuating an output vector obtained by combining first and second input vectors corresponding to signals from first and second sensors of the first pair of sensors by an attenuation factor which is a function of a difference in phase between the first and second input vectors.

29. The system of claim 28, wherein combining comprises summing.

30. The system of claim 28, wherein combining comprises differencing.

31. The system of claim 28, wherein the at least one circuit is further adapted to apply to at least one of the first and second processes sensitivity matching to accommodate system and/or signal mismatch.

32. The system of claim 31, wherein the sensitivity matching is based on a mathematical mean determination selected from the set of:

arithmetic mean, geometric mean, harmonic mean and, a root-mean-square (rms), determinations.

33. The system of claim 28, wherein the first and second pair of sensors are arranged in a one-dimensional array.

34. The system of claim 28. wherein the first and second pair of sensors are arranged in a two-dimensional array.

35. The system of claim 28, wherein the first and second pair of sensors are arranged in a three-dimensional array.