System and method for characterizing, synthesizing, and/or canceling out acoustic signals from inanimate sound sources

• US 20080004861A1
• Filed: 09/06/2007
• Published: 01/03/2008
• Est. Priority Date: 12/02/1998
• Status: Active Grant

• Current Assignee: Lawrence Livermore National Security LLC (Government of the United States of America)
• Original Assignee: Regents of the University of California (University of California)
• Inventors: Ng, Lawrence, Burnett, Greg, Holzrichter, John
• Granted Patent: US 8,447,585 B2
• Time in Patent Office: Days
• US Class Current: 704/2
• CPC Class Codes: G01H 1/12 of longitudinal or not specified vibrations
• CPC Class Codes: G01H 3/00 Measuring characteristics of vibrations by using a detector in a fluid G01H7/00, G01H9/00, G01H11/00 take precedence
• CPC Class Codes: G01H 9/00 Measuring mechanical vibrations or ultrasonic, sonic or infrasonic waves by using radiation-sensitive means, e.g. optical means
• CPC Class Codes: G01N 2291/02491 Materials with nonlinear acoustic properties
• CPC Class Codes: G01N 2291/02836 Flow rate, liquid level
• CPC Class Codes: G01N 2291/02872 Pressure
• CPC Class Codes: G06F 18/256 of results relating to different input data, e.g. multimodal recognition
• CPC Class Codes: G06V 40/10 Human or animal bodies, e.g. vehicle occupants or pedestrians; Body parts, e.g. hands
• CPC Class Codes: G10K 11/16 Methods or devices for protecting against, or for damping, noise or other acoustic waves in general G10K11/36 takes precedence
• CPC Class Codes: G10L 15/02 Feature extraction for speech recognition; Selection of recognition unit
• CPC Class Codes: G10L 15/24 Speech recognition using non-acoustical features
• CPC Class Codes: G10L 19/00 Speech or audio signals analysis-synthesis techniques for redundancy reduction, e.g. in vocoders; Coding or decoding of speech or audio signals, using source filter models or psychoacoustic analysis in musical instruments G10H
• CPC Class Codes: G10L 21/0272 Voice signal separating

Abstract

A system and method for characterizing, synthesizing, and/or canceling out acoustic signals from inanimate sound sources is disclosed. Propagating wave electromagnetic sensors monitor excitation sources in sound producing systems, such as machines, musical instruments, and various other structures. Acoustical output from these sound producing systems is also monitored. From such information, a transfer function characterizing the sound producing system is generated. From the transfer function, acoustical output from the sound producing system may be synthesized or canceled. The methods disclosed enable accurate calculation of matched transfer functions relating specific excitations to specific acoustical outputs. Knowledge of such signals and functions can be used to effect various sound replication, sound source identification, and sound cancellation applications.

Claims

1. A method for characterizing an inanimate sound source, comprising the steps of:

directly measuring excitations from the inanimate sound source;

directly measuring acoustic emissions from the inanimate sound source; and

generating, from the excitations and the acoustic emissions, functions which represent the inanimate sound source.

2. The method of claim 1 further comprising the step of:

measuring obscured and extended excitations using an excitation sensor.

3. The method of claim 1 further comprising the step of:

enhancing signals generated by an excitation sensor, which measures the excitations, by attaching electromagnetic wave reflecting structures to the inanimate sound source.

4. The method of claim 1 wherein the step of directly measuring excitations comprises the step of:

measuring excitations corresponding to fluid pressure variations.

5. The method of claim 1 wherein the step of directly measuring excitations comprises the step of:

measuring excitations corresponding to volume fluid flow variations.

6. The method of claim 1 wherein the step of directly measuring excitations comprises the step of:

measuring excitations corresponding to mechanical vibration amplitudes.

7. The method of claim 1 wherein the step of directly measuring excitations comprises the steps of:

generating a measured excitation function from the excitations; and

generating a parameterized excitation function from the measured excitation function.

8. The method of claim 7 wherein the step of generating a parameterized excitation function comprises the steps of:

parsing the measured excitation function into a series of pitch periods;

parsing the measured excitation function into a series of time frames over which a subset of the series of pitch periods remains substantially constant;

selecting at least one mathematical equation and corresponding set of coefficients which together match the measured excitation function to a predetermined accuracy; and

identifying the equation and coefficients as the parameterized excitation function.

9. The method of claim 8 wherein the step of generating a function comprises the step of:

generating a transfer function and associated coefficients which represent the inanimate sound source.

10. The method of claim 8 further comprising the step of:

generating an excitation feature vector for each time frame, containing the subset of the series of pitch periods and the parameterized excitation function.

11. The method of claim 10 further comprising the step of:

associating the excitation feature vector with a sound symbol in a musical sound description language.

12. The method of claim 1 wherein the step of directly measuring acoustic emissions comprises the steps of:

generating a first measured acoustic function from the acoustic emissions; and

generating a parameterized acoustic function from the first measured acoustic function.

13. The method of claim 12 wherein the step of generating a parameterized acoustic function comprises the steps of:

time-correlating the measured acoustic function with the measured excitation function; and

storing the time-correlation in a feature vector.

14. The method of claim 12:

wherein the step of generating a first measured acoustic function results in a first channel of audio information on the inanimate sound source; and

further comprising the step of generating a second measured acoustic function from the acoustic emissions substantially simultaneous with generating the first measured acoustic function so as to obtain a second channel of audio information from the inanimate sound source.

15. The method of claim 1 wherein the step of generating a function comprises the steps of:

generating a transfer function and associated coefficients which represent the inanimate sound source; and

deconvolving the excitations from the acoustic emissions to generate the transfer function.

16. The method of claim 1:

wherein the step of generating a function includes the step of, generating a transfer function and associated coefficients which represent the inanimate sound source; and

further comprising the steps of, storing the transfer function and associated coefficients in a transfer function feature vector; and

modifying the transfer function and associated coefficient to form a modified transfer function feature vector.

17. The method of claim 1 wherein the step of generating a function further comprises the step of:

generating a digital filter function and associated coefficients which represent the inanimate sound source.

18. A method for characterizing an inanimate sound source, comprising the steps of:

generating a measured primary excitation function from excitations of the inanimate sound source;

generating a parameterized primary excitation function from the measured excitation function;

subtracting the parameterized primary excitation function from the measured primary excitation function to create an estimated secondary excitation function;

selecting a chaotic excitation function from a set of chaotic excitation functions which best fits the estimated secondary excitation function;

identifying the chaotic excitation function as a parameterized secondary excitation function;

characterizing acoustic emissions from the inanimate sound source; and

generating, from the parameterized primary excitation function, from the parameterized secondary excitation function, and from the acoustic emissions, a function which represents the inanimate sound source.

19. The method of claim 18 wherein the step of selecting a chaotic excitation function comprises the steps of:

deconvolving the estimated secondary excitation function with each of the set of chaotic excitation functions to generate a set of error functions; and

selecting the chaotic excitation function from the set of chaotic excitation functions associated with a smallest error function in the set of error functions.

20. A method for characterizing an inanimate sound source, comprising the steps of:

generating a parameterized primary excitation function from primary excitations of the inanimate sound source;

generating a parameterized secondary excitation function from secondary excitations of the inanimate sound source using a second EM sensor;

generating a parameterized acoustic function from acoustic emissions of the inanimate sound source;

calculating a primary transfer function from the parameterized primary excitation function and the parameterized acoustic function, whereby primary excitations of the inanimate sound source are characterized;

convolving the parameterized primary excitation function and the primary transfer function to generate an estimated primary acoustic function;

subtracting the estimated primary acoustic function from the parameterized acoustic function to generate an estimated secondary acoustic function; and

calculating a secondary transfer function from the parameterized secondary excitation function and the estimated secondary acoustic function, whereby secondary excitations of the inanimate sound source are characterized.

21. The method of claim 20 wherein the step of generating a parameterized secondary excitation function comprises the steps of:

calculating a primary time frame based on the parameterized primary excitation function; and

calculating a secondary time frame based on the primary time frame in preparation for generating the parameterized secondary excitation function.

22. A method for characterizing an inanimate sound source, comprising the steps of:

generating a parameterized primary excitation function from primary excitations of the inanimate sound source;

generating a parameterized acoustic function from acoustic emissions of the inanimate sound source;

calculating a primary transfer function from the parameterized primary excitation function and the parameterized acoustic function, whereby primary excitations of the inanimate sound source are characterized;

convolving the parameterized primary excitation function and the primary transfer function to generate an estimated primary acoustic function;

subtracting the estimated primary acoustic function from the parameterized acoustic function to generate an estimated secondary acoustic function;

retrieving a pre-selected excitation function; and

calculating a secondary transfer function from the pre-selected excitation function and the estimated secondary acoustic function, whereby secondary excitations of the inanimate sound source are characterized.

23. A method for synthesizing acoustic signals using previously measured excitations and acoustic signals from an inanimate sound source, comprising the steps of:

receiving synthesis instructions;

retrieving a primary excitation function, which was previously measured and stored in a memory, based on the synthesis instructions;

retrieving a primary transfer function, derived from previously measured excitation and acoustic information and stored in the memory, based on the synthesis instructions; and

convolving the primary excitation function with the primary transfer function to synthesize a first acoustic signal.

24. The method of claim 23 wherein the step of convolving comprises the step of:

adjusting a duration of the primary excitation function so as to fit a pre-defined time frame.

25. The method of claim 23 wherein the step of convolving comprises the step of:

slowly changing the primary transfer function over several time frames so as to blend the first acoustic signal into a next acoustic signal.

26. The method of claim 23 wherein the step of convolving comprises the step of:

changing the primary excitation function amplitude abruptly by altering a time frame originally associated with the primary excitation function.

27. The method of claim 23 further comprising the step of:

concatenating the first acoustic signal associated with a first time frame with a second acoustic signal associated with a second time frame to produce a composite acoustic signal.

28. The method of claim 23 further comprising the steps of:

retrieving a secondary excitation function from a memory based on the synthesis instructions;

retrieving a secondary transfer function from the memory based on the synthesis instructions;

convolving the secondary excitation function with the secondary transfer function to synthesize a second acoustic signal; and

adding the second acoustic signal to the first acoustic signal to synthesize a composite acoustic signal.

29. The method of claim 28 further comprising the step of:

synchronizing the first and second acoustic signals to a time frame derived from the primary excitation function.

30. The method of claim 23 further comprising the steps of:

retrieving a pre-stored acoustic signal from the memory; and

adding the pre-stored acoustic signal to the first acoustic signal to synthesize a composite acoustic signal.

31. The method of claim 23 further comprising the steps of:

synthesizing a set of acoustic signals using parallel processing techniques; and

adding the set of acoustic signals to the first acoustic signal to synthesize a composite acoustic signal.

32. A method for identifying an inanimate sound source, comprising the steps of:

directly measuring an excitation function from excitations of the inanimate sound source;

directly measuring an acoustic function from acoustic emissions of the inanimate sound source;

calculating a transfer function from the excitation function and the acoustic function;

comparing the transfer function to a set of pre-stored transfer functions corresponding to a set of known inanimate sound sources; and

identifying the inanimate sound source as one in the set of known inanimate sound sources whose transfer function best matches the transfer function of the inanimate sound source.

33. The method of claim 32 wherein the step of generating an excitation function further comprises the step of:

generating an excitation function from purposefully induced excitations of the inanimate sound source.

34. A system for characterizing an inanimate sound source, comprising:

means for directly measuring excitations from the inanimate sound source;

means for directly measuring acoustic emissions from the inanimate sound source; and

means for generating, from the excitations and the acoustic emissions, a function which represents the inanimate sound source.

35. The system of claim 34 wherein the means for directly measuring excitations comprises:

means for generating a measured excitation function from the excitations; and

means for generating a parameterized excitation function from the measured excitation function.

36. The system of claim 35 wherein the means for generating a parameterized excitation function comprises:

means for parsing the measured excitation function into a series of pitch periods;

means for parsing the measured excitation function into a series of time frames over which a subset of the series of pitch periods remains substantially constant;

means for selecting at least one mathematical equation and corresponding set of coefficients which together match the measured excitation function to a predetermined accuracy; and

means for identifying the equation and coefficients as the parameterized excitation function.

37. The system of claim 36 wherein the means for generating a function comprises:

means for generating a transfer function and associated coefficients which represent the inanimate sound source.

38. The system of claim 36 further comprising:

means for generating an excitation feature vector for each time frame, containing the subset of the series of pitch periods and the parameterized excitation function.

39. The system of claim 34 wherein the means for characterizing acoustic emissions comprises:

means for generating a first measured acoustic function from the acoustic emissions; and

means for generating a parameterized acoustic function from the first measured acoustic function.

40. The system of claim 34 wherein the means for generating a function further comprises:

means for generating a digital filter function and associated coefficients which represent the inanimate sound source.

41. A system for characterizing an inanimate sound source, comprising:

means for generating a measured primary excitation function from excitations of the inanimate sound source;

means for generating a parameterized primary excitation function from the measured excitation function;

means for subtracting the parameterized primary excitation function from the measured primary excitation function to create an estimated secondary excitation function;

means for selecting a chaotic excitation function from a set of chaotic excitation functions which best fits the estimated secondary excitation function;

means for identifying the chaotic excitation function as a parameterized secondary excitation function;

means for characterizing acoustic emissions from the inanimate sound source; and

means for generating, from the parameterized primary excitation function, from the parameterized secondary excitation function, and from the acoustic emissions, a function which represents the inanimate sound source.

42. The system of claim 41 wherein the means for selecting a chaotic excitation function comprises:

means for deconvolving the estimated secondary excitation function with each of the set of chaotic excitation functions to generate a set of error functions; and

means for selecting the chaotic excitation function from the set of chaotic excitation functions associated with a smallest error function in the set of error functions.

43. A system for characterizing an inanimate sound source, comprising:

means for generating a parameterized primary excitation function from primary excitations of the inanimate sound source;

means for generating a parameterized secondary excitation function from secondary excitations of the inanimate sound source using a second EM sensor;

means for generating a parameterized acoustic function from acoustic emissions of the inanimate sound source;

means for calculating a primary transfer function from the parameterized primary excitation function and the parameterized acoustic function, whereby primary excitations of the inanimate sound source are characterized;

means for convolving the parameterized primary excitation function and the primary transfer function to generate an estimated primary acoustic function;

means for subtracting the estimated primary acoustic function from the parameterized acoustic function to generate an estimated secondary acoustic function; and

means for calculating a secondary transfer function from the parameterized secondary excitation function and the estimated secondary acoustic function, whereby secondary excitations of the inanimate sound source are characterized.

44. A system for characterizing an inanimate sound source, comprising:

means for generating a parameterized primary excitation function from primary excitations of the inanimate sound source;

means for generating a parameterized acoustic function from acoustic emissions of the inanimate sound source;

means for calculating a primary transfer function from the parameterized primary excitation function and the parameterized acoustic function, whereby primary excitations of the inanimate sound source are characterized;

means for convolving the parameterized primary excitation function and the primary transfer function to generate an estimated primary acoustic function;

means for subtracting the estimated primary acoustic function from the parameterized acoustic function to generate an estimated secondary acoustic function;

means for retrieving a pre-selected excitation function; and

means for calculating a secondary transfer function from the pre-selected excitation function and the estimated secondary acoustic function, whereby secondary excitations of the inanimate sound source are characterized.

45. A system for synthesizing acoustic signals representing an inanimate sound source using previously measured excitations and acoustic signals, comprising:

means for receiving synthesis instructions;

means for retrieving a previously measured primary excitation function from a memory based on the synthesis instructions;

means for retrieving a primary transfer function, derived from previously measured excitation and acoustic information and stored in the memory, based on the synthesis instructions; and

means for convolving the primary excitation function with the primary transfer function to synthesize a first acoustic signal.

46. The system of claim 45 further comprising:

means for retrieving a secondary excitation function from a memory based on the synthesis instructions;

means for retrieving a secondary transfer function from the memory based on the synthesis instructions;

means for convolving the secondary excitation function with the secondary transfer function to synthesize a second acoustic signal; and

means for adding the second acoustic signal to the first acoustic signal to synthesize a composite acoustic signal.

47. The system of claim 45 further comprising:

means for retrieving a pre-stored acoustic signal from the memory; and

means for adding the pre-stored acoustic signal to the first acoustic signal to synthesize a composite acoustic signal.

48. A system for identifying an inanimate sound source, comprising:

means for directly measuring an excitation function from excitations of the inanimate sound source;

means for directly measuring an acoustic function from acoustic emissions of the inanimate sound source;

means for calculating a transfer function from the excitation function and the acoustic function;

means for comparing the transfer function to a set of pre-stored transfer functions corresponding to a set of known inanimate sound sources; and

means for identifying the inanimate sound source as one in the set of known inanimate sound sources whose transfer function best matches the transfer function of the inanimate sound source.

49. A computer-usable medium embodying computer program code for causing a computer to characterize an inanimate sound source, by performing the steps of:

directly measuring excitations from the inanimate sound source;

directly measuring acoustic emissions from the inanimate sound source; and

generating, from the excitations and the acoustic emissions, a function which represents the inanimate sound source.

50. The computer-usable medium of claim 49 wherein the step of directly measuring excitations comprises the steps of:

generating a measured excitation function from the excitations; and

generating a parameterized excitation function from the measured excitation function.

51. The computer-usable medium of claim 50 wherein the step of generating a parameterized excitation function comprises the steps of:

parsing the measured excitation function into a series of pitch periods;

parsing the measured excitation function into a series of time frames over which a subset of the series of pitch periods remains substantially constant;

selecting at least one mathematical equation and corresponding set of coefficients which together match the measured excitation function to a predetermined accuracy; and

identifying the equation and coefficients as the parameterized excitation function.

52. The computer-usable medium of claim 51 wherein the step of generating a function comprises the step of:

generating a transfer function and associated coefficients which represent the inanimate sound source.

53. The computer-usable medium of claim 51 further performing the step of:

generating an excitation feature vector for each time frame, containing the subset of the series of pitch periods and the parameterized excitation function.

54. The computer-usable medium of claim 49 wherein the step of directly measuring acoustic emissions comprises the steps of:

generating a first measured acoustic function from the acoustic emissions; and

generating a parameterized acoustic function from the first measured acoustic function.

55. The computer-usable medium of claim 49 wherein the step of generating a function further comprises the step of:

generating a digital filter function and associated coefficients which represent the inanimate sound source.

56. A computer-usable medium embodying computer program code for causing a computer to characterize an inanimate sound source, by performing the steps of:

generating a measured primary excitation function from excitations of the inanimate sound source;

generating a parameterized primary excitation function from the measured excitation function;

subtracting the parameterized primary excitation function from the measured primary excitation function to create an estimated secondary excitation function;

selecting a chaotic excitation function from a set of chaotic excitation functions which best fits the estimated secondary excitation function;

identifying the chaotic excitation function as a parameterized secondary excitation function;

characterizing acoustic emissions from the inanimate sound source; and

generating, from the parameterized primary excitation function, from the parameterized secondary excitation function, and from the acoustic emissions, a function which represents the inanimate sound source.

57. The computer-usable medium of claim 56 wherein the step of selecting a chaotic excitation function comprises the steps of:

deconvolving the estimated secondary excitation function with each of the set of chaotic excitation functions to generate a set of error functions; and

selecting the chaotic excitation function from the set of chaotic excitation functions associated with a smallest error function in the set of error functions.

58. A computer-usable medium embodying computer program code for causing a computer to characterize an inanimate sound source, by performing the steps of:

generating a parameterized primary excitation function from primary excitations of the inanimate sound source;

generating a parameterized secondary excitation function from secondary excitations of the inanimate sound source using a second EM sensor;

generating a parameterized acoustic function from acoustic emissions of the inanimate sound source;

calculating a primary transfer function from the parameterized primary excitation function and the parameterized acoustic function, whereby primary excitations of the inanimate sound source are characterized;

convolving the parameterized primary excitation function and the primary transfer function to generate an estimated primary acoustic function;

subtracting the estimated primary acoustic function from the parameterized acoustic function to generate an estimated secondary acoustic function; and

calculating a secondary transfer function from the parameterized secondary excitation function and the estimated secondary acoustic function, whereby secondary excitations of the inanimate sound source are characterized.

59. A computer-usable medium embodying computer program code for causing a computer to characterize an inanimate sound source, by performing the steps of:

generating a parameterized primary excitation function from primary excitations of the inanimate sound source;

generating a parameterized acoustic function from acoustic emissions of the inanimate sound source;

calculating a primary transfer function from the parameterized primary excitation function and the parameterized acoustic function, whereby primary excitations of the inanimate sound source are characterized;

convolving the parameterized primary excitation function and the primary transfer function to generate an estimated primary acoustic function;

subtracting the estimated primary acoustic function from the parameterized acoustic function to generate an estimated secondary acoustic function;

retrieving a pre-selected excitation function; and

calculating a secondary transfer function from the pre-selected excitation function and the estimated secondary acoustic function, whereby secondary excitations of the inanimate sound source are characterized.

60. A computer-usable medium embodying computer program code for causing a computer to synthesizing acoustic signals representing an inanimate sound source using previously measured excitations and acoustic signals, by performing the steps of:

receiving synthesis instructions;

retrieving from memory a primary excitation function, previously measured and stored in the memory, based on the synthesis instructions;

retrieving from memory a primary transfer function, derived from previously measured excitation and acoustic information both stored in the memory, based on the synthesis instructions; and

convolving the primary excitation function with the primary transfer function to synthesize a first acoustic signal.

61. The computer-usable medium of claim 60 further by performing the steps of:

retrieving a secondary excitation function from a memory based on the synthesis instructions;

retrieving a secondary transfer function from the memory based on the synthesis instructions;

convolving the secondary excitation function with the secondary transfer function to synthesize a second acoustic signal; and

adding the second acoustic signal to the first acoustic signal to synthesize a composite acoustic signal.

62. The computer-usable medium of claim 60 further by performing the steps of:

retrieving a pre-stored acoustic signal from the memory; and

adding the pre-stored acoustic signal to the first acoustic signal to synthesize a composite acoustic signal.

63. A computer-usable medium embodying computer program code for causing a computer to canceling out acoustic signals from an inanimate sound source, by performing the steps of:

directly measuring an excitation function from excitations of the inanimate sound source;

directly measuring an acoustic function from acoustic emissions of the inanimate sound source;

calculating a transfer function from the excitation function and the acoustic function;

receiving cancellation instructions;

convolving an instant excitation function with the previously obtained transfer function to synthesize an instant canceling acoustic signal; and

broadcasting said instant canceling acoustic signal proximate to the acoustic emissions.

64. A computer-usable medium embodying computer program code for causing a computer to identify an inanimate sound source, by performing the steps of:

directly measuring an excitation function from excitations of the inanimate sound source;

generating an acoustic function from acoustic emissions of the inanimate sound source;

calculating a transfer function from the measured excitation function and the measured acoustic function;

comparing the transfer function to a set of pre-stored transfer functions corresponding to a set of known inanimate sound sources; and

identifying the inanimate sound source as one in the set of known inanimate sound sources whose transfer function best matches the transfer function of the inanimate sound source.

65. A system for characterizing acoustic signals from an inanimate sound source, comprising:

a first electromagnetic (EM) sensor directly measuring primary excitations from the inanimate sound source;

a first acoustic sensor directly measuring a first set of acoustic emissions from the inanimate sound source;

an EM processor, coupled to the EM sensor, for converting the directly measuring primary excitations into a primary excitation function;

an acoustic processor, coupled to the acoustic sensor, for converting the first set of directly measuring acoustic emissions into a first acoustic function;

a transfer function processor, coupled to the EM processor and the acoustic processor, for generating a primary transfer function from the primary excitation function and the first acoustic function.

66. The system of claim 65 further comprising:

a second EM sensor directly measuring secondary excitations from the inanimate sound source.

67. The system of claim 65 further comprising:

a second acoustic sensor directly measuring a second set of acoustic emissions from the inanimate sound source.

68. A system for synthesizing acoustic signals from an inanimate sound source using previously measured excitations and acoustic signals, comprising:

a memory containing a primary excitation function and a primary transfer function;

a synthesis control unit for generating synthesis instructions; and

a synthesis processor, coupled to the synthesis control unit and the memory, for retrieving the previously measured primary excitation function and the previously derived primary transfer function, derived from previously measured excitation and acoustic information, and for convolving the primary excitation function with the primary transfer function to synthesize a first acoustic signal.

69. The system of claim 68, further comprising:

a concatenation unit, coupled to the synthesis processor, for linking the first acoustic signal with any prior acoustic signals; and

a broadcasting unit, coupled to the concatenation unit, for translating the acoustic signals into audible acoustic emissions.

70. A system for canceling out acoustic signals from an inanimate sound source, comprising:

an electromagnetic processor for directly measuring an excitation function from excitations of the inanimate sound source;

an acoustic processor for directly measuring an acoustic function from acoustic emissions of the inanimate sound source;

a transfer function processor, coupled to the electromagnetic processor and the acoustic processor, for calculating a transfer function from the excitation function and the acoustic function;

a synthesis processor, coupled to the transfer function processor, for receiving cancellation instructions, for convolving the instant excitation function with the previously derived transfer function to synthesize a canceling acoustic signal; and

a broadcasting unit, coupled to the synthesis processor, for broadcasting the canceling acoustic signal proximate to the acoustic emissions.

71. A method for characterizing an inanimate sound source, comprising the steps of:

directly measuring auxiliary excitations from said inanimate sound source;

generating an excitation function from said measured auxiliary excitations;

directly measuring acoustic emissions from said inanimate sound source; and

generating, from said measured auxiliary and generated excitation functions, and said measured acoustic emissions, functions which characterize the sound output from an inanimate sound source.

72. The method for characterizing an inanimate sound source of claim 71, wherein said step of generating an excitation function from said measured auxiliary excitations includes generating excitation period timing information defining onset, duration, and end of excitation periods.

73. The method for characterizing an inanimate sound source of claim 71, wherein an EM sensor is utilized for said step of directly measuring auxiliary excitations from said inanimate sound source;

and wherein said EM sensor transmits coherent EM waves toward said inanimate sound source, receives reflected EM waves from said inanimate sound source, and processes said received waves using homodyne, heterodyne, or other correlation techniques.

74. The method of claim 71 wherein said functions which characterize the sound output from an inanimate sound source are transfer functions or their corresponding filter functions.

75. A method for characterizing inanimate sound excitations, comprising the steps of:

measuring movements of an excitation subsystem with a coherent wave EM sensor, and

calculating a measured excitation function from said movements.

76. The method of claim 75, where said EM sensor transmits a coherent packet of EM waves, or transmits a continuous sequence of EM waves, and receives reflected EM waves using a homodyne receiver, or a heterodyne receiver, or any correlation-function receiver.

77. The method of claim 75 a where said EM sensor measures the movements of the excitation subsystem, without contact to the subsystem, in the near field, intermediate field, or far field.