Characterizing, synthesizing, and/or canceling out acoustic signals from sound sources

• US 20030149553A1
• Filed: 01/22/2003
• Published: 08/07/2003
• 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: Holzrichter, John F.
• Granted Patent: US 7,191,105 B2
• Time in Patent Office: Days
• US Class Current: 703/2
• 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 for characterizing, synthesizing, and/or canceling out acoustic signals from inanimate and animate sound sources. Electromagnetic sensors monitor excitation sources in sound producing systems, such as animate sound sources such as the human voice, or from 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 systems disclosed enable accurate calculation of 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 of characterizing a sound source, comprising the steps of:

characterizing excitations from the sound source;

characterizing acoustic emissions from the sound source; and

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

2. The method of claim 1 wherein said step of characterizing excitations comprises measuring excitations corresponding to direct or auxiliary mechanical vibration amplitudes.

3. The method of claim 1 wherein said step of characterizing excitations comprises using coherent EM wave sensors for characterizing said excitation functions.

4. The method of claim 1 wherein said step of generating a function comprises generating a transfer function and associated coefficients which represent the sound source;

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

5. A method of characterizing a sound source, comprising the steps of:

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

6. The method of claim 5 wherein said step of generating a measured primary excitation function comprises using a coherent EM wave sensor for generating said measured primary excitation function.

7. A method of characterizing a sound source, comprising the steps of:

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

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

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

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

8. The method of claim 7 wherein said step of generating a parameterized primary excitation function comprises using a coherent EM wave sensor for generating said parameterized primary excitation function.

9. A method of characterizing a sound source, comprising the steps of:

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

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

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

10. The method of claim 9 wherein said step of generating a parameterized primary excitation function comprises using a coherent EM sensor for generating said parameterized primary excitation function.

11. A method for canceling out acoustic signals from a sound source, comprising the steps of:

generating an excitation function from excitations of the sound source;

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

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

receiving cancellation instructions;

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

broadcasting the canceling acoustic signal proximate to the acoustic emissions.

12. The method of claim 11 wherein the step of generating an excitation function further comprises the step of, instantly generating an excitation function from excitations of the sound source;

further comprising the step of;

storing the transfer function in memory and in a transfer function processor; and

wherein the step of convolving the excitation function further includes the step of,

convolving the instantly generated excitation function with the transfer function stored in the memory to synthesize a canceling acoustic signal.

13. The method of claim 11 wherein said step of generating an excitation function further comprises the step of:

selecting a default time frame based on a reverberation time of the sound source.

15. The method of claim 11 wherein said step of generating an excitation function further comprises the step of:

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

14. A method of identifying a sound source, comprising the steps of:

generating an excitation function from excitations of the sound source;

generating an acoustic function from acoustic emissions of the 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 sound sources; and

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

16. A system for characterizing a sound source, comprising:

means for characterizing excitations from the sound source;

means for characterizing acoustic emissions from the sound source; and

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

17. The system of claim 16 wherein the means for generating a function further comprises:

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

18. A system for characterizing a sound source, comprising:

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

19. A system for characterizing a sound source, comprising:

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

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

means for generating a parameterized acoustic function from acoustic emissions of the 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 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 sound source are characterized.

20. A system for characterizing a sound source, comprising:

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

means for generating a parameterized acoustic function from acoustic emissions of the 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 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 sound source are characterized.

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

means for generating an excitation function from excitations of the sound source;

means for generating an acoustic function from acoustic emissions of the sound source;

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

means for receiving cancellation instructions;

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

means for broadcasting the canceling acoustic signal proximate to the acoustic emissions.

22. A system for identifying a sound source, comprising:

means for generating an excitation function from excitations of the sound source;

means for generating an acoustic function from acoustic emissions of the 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 sound sources; and

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

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

characterizing excitations from the sound source;

characterizing acoustic emissions from the sound source; and

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

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

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

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

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

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

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

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

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

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

26. A computer-usable medium embodying computer program code for causing a computer to synthesizing acoustic signals representing a sound source, by performing the steps of:

receiving synthesis instructions;

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

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

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

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

generating an excitation function from excitations of the sound source;

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

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

receiving cancellation instructions;

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

broadcasting the canceling acoustic signal proximate to the acoustic emissions.

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

generating an excitation function from excitations of the sound source;

generating an acoustic function from acoustic emissions of the 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 sound sources; and

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

29. A system for characterizing acoustic signals from a sound source, comprising:

a first electromagnetic (EM) sensor monitoring primary excitations from the sound source;

a first acoustic sensor monitoring a first set of acoustic emissions from the sound source;

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

an acoustic processor, coupled to the acoustic sensor, for converting the first set of 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.

30. The system of claim 29 further comprising:

a second EM sensor monitoring secondary excitations from the sound source.

31. The system of claim 29 further comprising:

a second acoustic sensor monitoring a second set of acoustic emissions from the sound source.

32. A system for synthesizing acoustic signals from a sound source, 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 primary excitation function and the primary transfer function, and for convolving the primary excitation function with the primary transfer function to synthesize a first acoustic signal.

33. A system for canceling out acoustic signals from a sound source, comprising:

an electromagnetic processor for generating an excitation function from excitations of the sound source;

an acoustic processor for generating an acoustic function from acoustic emissions of the 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 excitation function with the 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.