System and method for characterizing voiced excitations of speech and acoustic signals, removing acoustic noise from speech, and synthesizing speech

• US 6,377,919 B1
• Filed: 11/04/1999
• Issued: 04/23/2002
• Est. Priority Date: 02/06/1996
• Status: Expired due to Fees

• 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 C., Burnett, Greg C., Holzrichter, John F.
• Primary Examiner(s): Tsang, Fan
• Assistant Examiner(s): Opsasnick, Michael N.
• Application Number:
  US09/433,453
• Time in Patent Office: 901 Days
• Field of Search: 704/231, 704/235, 704/219, 704/261, 704/251, 704/271, 847/25, 623/9, 600/538, 600/595
• US Class Current: 704/231
• CPC Class Codes: A61B 5/0507 using microwaves or terahertz waves
• CPC Class Codes: A61B 5/7257 using Fourier transforms
• CPC Class Codes: G01N 2291/02491 Materials with nonlinear acoustic properties
• 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: G10L 13/04 Details of speech synthesis systems, e.g. synthesiser structure or memory management
• CPC Class Codes: G10L 15/24 Speech recognition using non-acoustical features

Abstract

Low power EM waves are used to detect motions of vocal tract tissues of the human speech system before, during, and after voiced speech. A voiced excitation function is derived. The excitation function provides speech production information to enhance speech characterization and to enable noise removal from human speech.

Claims

1. A method for characterizing voiced excitations of speech, comprising the steps of:

directing EM wave radiation through the air toward a predetermined portion of a vocal tract;

measuring movement of said predetermined portion of a vocal tract with a EM sensor spaced from said predetermined portion of a vocal tract;

calculating an air pressure function corresponding to the movements; and

calculating a voiced excitation function from said air pressure function.

2. The method of claim 1:

wherein the measuring step includes the step of;

measuring movement in a sub-glottal region of the vocal tract; and

wherein the calculating a pressure step includes the step of;

calculating a sub-glottal pressure function.

3. The method of claim 2, wherein the calculating a pressure step includes the step of:

calculating a supra-glottal pressure function from the sub-glottal pressure function.

4. The method of claim 1:

wherein the measuring step includes the step of;

measuring movement in a supra-glottal region of the vocal tract; and

wherein the calculating a pressure step includes the step of;

calculating a supra-glottal pressure function.

5. The method of claim 1:

further including the step of,

dividing the voiced excitation function into time frames;

wherein the measuring step includes the step of,

measuring an acoustic signal produced by the vocal tract corresponding to a time frame; and

further including the steps of;

deconvolving the voiced excitation function from the acoustic signal to create a voiced speech transfer function.

6. The method of claim 5, further including the steps of:

parameterizing the voiced speech transfer function; and

calculating real-time filter coefficients of the voiced speech transfer function.

7. A method for characterizing acoustic speech, comprising the steps of:

directing EM wave radiation through the air toward a predetermined portion of a tissue interface;

measuring movement of said predetermined portion of a tissue interface with a EM sensor spaced from said predetermined portion of a vocal tract;

calculating an air pressure signal corresponding to the movements; and

formulating an acoustic speech signal from the air pressure signal.

8. The method of claim 7, wherein the measuring step includes the step of:

measuring movement of a predetermined portion of a vocal tract wall.

9. A method for measuring speech articulators, comprising the steps of:

directing EM wave radiation through the air toward a first predetermined portion of a tissue interface;

measuring movement of said first predetermined portion of a tissue interface with a EM sensor spaced from said predetermined portion of a vocal tract;

directing EM wave radiation through the air toward a second predetermined portion of a tissue interface; and

measuring movement of a second predetermined portion of a tissue interface with an EM sensor spaced from said predetermined portion of a vocal tract.

10. A system for characterizing voiced excitations in speech, comprising;

a EM sensor for measuring movement of a predetermined portion of a vocal tract by responding to EM wave radiation that has been directed through the air toward said predetermined portion of a vocal tract, said EM sensor spaced from said predetermined portion of a vocal tract; and

a computer for,

calculating an air pressure function corresponding to the movements; and

calculating a voiced excitation function from said air pressure function.

11. A method for characterizing voiced excitations of speech, comprising the steps of:

directing EM wave radiation through the air toward a predetermined portion of a vocal tract;

measuring movement of said predetermined portion of a vocal tract with a EM wave sensor spaced from said predetermined portion of a vocal tract;

calculating an air pressure function corresponding to the movements; and

calculating a voiced excitation function from said air pressure function.

12. A method for characterizing voiced excitations of speech, comprising the steps of:

directing electromagnetic (EM) wave radiation through the air toward a predetermined portion of a vocal tract;

measuring movements of said predetermined portion of a vocal tract with a EM wave sensor spaced from said predetermined portion of a vocal tract, and

calculating an air pressure function corresponding to said movements.