APPARATUS, METHOD AND COMPUTER PROGRAM FOR LOCALIZING A SOUND SOURCE

• US 20110110531A1
• Filed: 12/17/2010
• Published: 05/12/2011
• Est. Priority Date: 06/20/2008
• Status: Active Grant

• Current Assignee: Fraunhofer Gesellschaft Zur Foerderung Der Angewandten Forsching E.V.
• Original Assignee: Fraunhofer Gesellschaft Zur Foerderung Der Angewandten Forsching E.V.
• Inventors: KLEFENZ, Frank, SPORER, Thomas
• Granted Patent: US 8,649,529 B2
• Time in Patent Office: Days
• US Class Current: 381/92
• CPC Class Codes: G01S 3/809 Rotating or oscillating beam systems using continuous analysis of received signal for determining direction in the plane of rotation or oscillation or for determining deviation from a predetermined direction in such a plane
• CPC Class Codes: H04R 3/005 for combining the signals of two or more microphones specially adapted for hearing aids H04R25/407

Abstract

An apparatus for localizing a sound source includes at least two rotatably arranged microphones, a drive formed to set the microphones into rotation, and an evaluator. The evaluator is formed to receive microphone signals of the at least two microphones, while the at least two microphones are moving, and to obtain information on a direction from which sound arrives from the sound source or information on a position of the sound source, using the microphone signals obtained during the movement of the microphones.

Claims

1. An apparatus for localizing a sound source, comprising:

at least two rotatably arranged microphones;

a drive formed to set the microphones into rotation; and

an evaluator formed to receive microphone signals of at least two microphones, while the at least two microphones are moving, and

to acquire information on a direction from which sound from the sound source arrives or information on a position of the sound source, using the microphone signals acquired during the movement of the microphones,

wherein the evaluator is formed to evaluate a Doppler frequency shift between a first microphone signal from a first one of the microphones and a second microphone signal from a second one of the microphones.

2. The apparatus according to claim 1, wherein the evaluator is formed to evaluate a phase relation between the microphone signals in order to acquire the information on the direction from which the sound arrives from the sound source or the information on the position of the sound source.

3. The apparatus according to claim 1, wherein the evaluator is formed to provide the information on the direction or the information on the position depending on at which orientation of the microphones phases of the first microphone signal and of the second microphone signal differ by no more than a given threshold value.

4. The apparatus according to claim 3, wherein the evaluator is formed to provide the information on the direction or the information on the position depending on at which orientation of the microphones phases of the first microphone signal and of the second microphone signal differ by no more than a given threshold value, and depending on a difference between an amplitude of the first microphone signal and an amplitude of the second microphone signal.

5. The apparatus according to claim 1, wherein the evaluator is formed to provide the information on the direction or the information on the position depending on at which orientation of the microphones a difference between the microphone signals of the microphones is within a given range with respect to an amplitude and with respect to a phase.

6. The apparatus according to claim 1, wherein the evaluator is formed to provide the information on the direction or the information on the position depending on at which orientation of the microphones a Doppler frequency shift between a first one of the microphone signals and a second one of the microphone signals and a phase shift between the first microphone signal and the second one of the microphone signals are within a given range.

7. The apparatus according to claim 6, wherein the evaluator is formed to select, depending on at which orientation of the microphones a Doppler frequency shift satisfies a given condition, an orientation from a plurality of orientations at which a difference between the microphone signals is within a given range with respect to an amplitude and with respect to a phase, and to provide the information on the direction or the information on the position depending on the selected orientation of the microphones.

8. The apparatus according to claim 1, wherein the evaluator is formed to evaluate information on an amount of the Doppler frequency shift between a first microphone signal from a first one of the microphones and a second microphone signal from a second one of the microphones, in order to acquire the information on the direction from which the sound arrives from the sound source or the information on the position of the sound source.

9. The apparatus according to claim 8, wherein the evaluator is formed to evaluate the information on an amount of the Doppler frequency shift between the first microphone signal and the second microphone signal, in order to acquire the information as to what distance a position of the sound source comprises from a plane in which at least one of the microphones moves.

10. The apparatus according to claim 1, wherein the evaluator is formed to evaluate information on a temporal course of a Doppler frequency shift between a first microphone signal from a first one of the microphones and a second microphone signal from a second one of the microphones, in order to acquire the information on the direction from which the sound arrives or the information on the position of the sound source.

11. The apparatus according to claim 10, wherein the evaluator is formed to evaluate a time duration between two characteristic points of a temporal course of the Doppler frequency shift, in order to acquire the information on the direction from which the sound arrives or the information on the position of the sound source.

12. The apparatus according to claim 10, wherein the evaluator is formed to evaluate information, at which orientation of the microphones a minimum or maximum Doppler frequency shift occurs between the first microphone signal and the second microphone signal, in order to acquire the information on the direction from which the sound arrives or the information on the position of the sound source.

13. The apparatus according to claim 1, wherein the evaluator is formed to superimpose a microphone signal from one of the microphones recorded at a first revolution of the rotation and a microphone signal recorded at a second revolution of the rotation, in order to improve a signal-to-noise ratio.

14. The apparatus according to claim 1, wherein the evaluator is formed to correlate a microphone signal from at least one of the microphones with a comparison signal, in order to distinguish a microphone signal proportion of a sound source to be localized from spurious microphone signal proportions.

15. The apparatus according to claim 1, wherein at least two microphones are arranged on a surface of a sphere.

16. The apparatus according to claim 1, wherein the at least two microphones are arranged on a surface of a star-shaped carrier, a disc, a ring, an x-bladed fan, a drum, a rim or a gyroscope.

17. The apparatus according to claim 1, wherein the apparatus comprises a position determiner for determining an orientation of the microphones.

18. The apparatus according to claim 17, wherein the apparatus is formed to calibrate the position determiner on the basis of an acoustic calibration signal from an acoustic beacon.

19. The apparatus according to claim 1, wherein the microphones are arranged such that main sensitivity directions of the microphones are oriented away from the center of the rotation.

20. The apparatus according to claim 1, wherein the microphones are arranged such that main sensitivity directions of the microphones are oriented tangentially with respect to a direction of movement of the microphones.

21. The apparatus according to claim 1, wherein the microphones are arranged such that main sensitivity directions of the microphones are oriented at least approximately perpendicularly to a plane in which the microphones move in a rotation.

22. The apparatus according to claim 1, wherein an acoustically hard separating body is arranged between the microphones.

23. The apparatus according to claim 1, wherein the drive is formed to drive the microphones so that the microphones perform between one fifth of a revolution per second and ten revolutions per second.

24. The apparatus according to claim 1, wherein the apparatus comprises a beacon formed to mark the position or direction.

25. The apparatus according to claim 1, wherein the apparatus comprises a further microphone, which is arranged at a center between the at least two rotatably arranged microphones, and

wherein the evaluator is formed to determine the information on the direction or the information on the position, using a microphone signal from the microphone arranged at the center.

26. The apparatus according to claim 1, wherein the apparatus comprises a further microphone, which is arranged above or below a plane of movement in which the rotatably arranged microphones move, and

wherein the evaluator is formed to determine the information on the direction or the information on the position, using a microphone signal from the further microphone.

27. The apparatus according to claim 1, wherein the drive is formed to set the rotatably arranged microphones into substantially uniform rotation.

28. The apparatus according to claim 1, wherein the apparatus comprises at least four rotatably arranged microphones M1, M2, M3, M4, which are arranged to perform rotation about a rotation center.

29. The apparatus according to claim 1, wherein the evaluator is formed to sample microphone signals from the microphones at a sampling rate, and

wherein the evaluator is formed to acquire information on the sampling rate on the basis of knowledge of a frequency of a sound signal originating from the sound source and using a plurality of samples.

30. The apparatus according to claim 1, wherein the evaluator is formed to determine an autocorrelation function of at least one of the microphone signals, in order to acquire the rotational speed at which the microphones move using the autocorrelation function.

31. The apparatus according to claim 1, wherein the evaluator is formed to determine the information on the direction or the information on the position, using information describing a phase offset between signals of two microphones temporarily in line with the sound source and using information on an amount of a Doppler shift.

32. The apparatus according to claim 1, wherein the evaluator is formed to determine the information on the direction or the information on the position, using information on a characteristic point of an envelope of a difference signal, wherein the difference signal describes a difference between microphone signals of at least two of the movable microphones.

33. A method of localizing a sound source, comprising:

acquiring microphone signals from at least two microphones, while the at least two microphones perform rotation; and

determining information on a direction from which sound arrives from the sound source or information on a position of the sound source, using the microphone signals acquired during the movement of the microphones,

wherein a Doppler frequency shift between a first microphone signal from a first one of the microphones and a second microphone signal from a second one of the microphones is evaluated.

34. The method according to claim 33, wherein determining information on a direction or information on a position comprises determining a sampling rate at which a microphone signal from one of the microphones is sampled, based on a known frequency of the audio signal and based on samples of the at least one microphone signal.

35. The method according to claim 33, wherein determining information on a direction or information on a position comprises determining a rotational speed of the rotation on the basis of an autocorrelation of at least one microphone signal.

36. The method according to claim 33, wherein determining information on a direction or information on a position comprises determining a distance of the microphones from a center and a speed of sound on the basis of a phase offset of two microphone signals and on the basis of an amount of a Doppler frequency shift between two microphone signals.

37. The method according to claim 33, wherein determining information on a direction or information on a position comprises determining a minimum of an envelope of a difference between two microphone signals.

38. A tangible computer readable medium having a computer program for performing, when the computer program is executed on a computer, a method of localizing a sound source, comprising:

acquiring microphone signals from at least two microphones, while the at least two microphones perform rotation; and

determining information on a direction from which sound arrives from the sound source or information on a position of the sound source, using the microphone signals acquired during the movement of the microphones, wherein a Doppler frequency shift between a first microphone signal from a first one of the microphones and a second microphone signal from a second one of the microphones is evaluated.

39. An apparatus for localizing a sound source, comprising:

at least two rotatably arranged microphones;

a drive formed to set the microphones into rotation; and

an evaluator formed to receive microphone signals of at least two microphones, while the at least two microphones are moving, and

to acquire information on a direction from which sound from the sound source arrives or information on a position of the sound source, using the microphone signals acquired during the movement of the microphones;

wherein the evaluator is formed to provide the information on the direction or the information on the position depending on at which orientation of the microphones a difference between the microphone signals of the microphones is within a given range with respect to an amplitude and with respect to a phase.

40. An apparatus for localizing a sound source, comprising:

at least two rotatably arranged microphones;

a drive formed to set the microphones into rotation; and

an evaluator formed to receive microphone signals of at least two microphones, while the at least two microphones are moving, and

to acquire information on a direction from which sound from the sound source arrives or information on a position of the sound source, using the microphone signals acquired during the movement of the microphones;

wherein the evaluator is formed to sample microphone signals from the microphones at a sampling rate, and

wherein the evaluator is formed to acquire information on the sampling rate on the basis of knowledge of a frequency of a sound signal originating from the sound source and using a plurality of samples.

41. An apparatus for localizing a sound source, comprising:

at least two rotatably arranged microphones;

a drive formed to set the microphones into rotation; and

an evaluator formed to receive microphone signals of at least two microphones, while the at least two microphones are moving, and

to acquire information on a direction from which sound from the sound source arrives or information on a position of the sound source, using the microphone signals acquired during the movement of the microphones;

wherein the evaluator is formed to determine an autocorrelation function of at least one of the microphone signals, in order to acquire the rotational speed at which the microphones move using the autocorrelation function.

42. An apparatus for localizing a sound source, comprising:

at least two rotatably arranged microphones;

a drive formed to set the microphones into rotation; and

an evaluator formed to receive microphone signals of at least two microphones, while the at least two microphones are moving, and

to acquire information on a direction from which sound from the sound source arrives or information on a position of the sound source, using the microphone signals acquired during the movement of the microphones;

wherein the evaluator is formed to determine the information on the direction or the information on the position, using information on a characteristic point of an envelope of a difference signal, wherein the difference signal describes a difference between microphone signals of at least two of the movable microphones.

43. An apparatus for localizing a sound source, comprising:

at least two rotatably arranged microphones,

wherein an acoustically hard separating body is arranged between the microphones;

a drive formed to set the microphones into rotation; and

an evaluator formed to receive microphone signals of at least two microphones, while the at least two microphones are moving, and

to acquire information on a direction from which sound from the sound source arrives or information on a position of the sound source, using the microphone signals acquired during the movement of the microphones.