Apparatus and Method for Detecting Speech Using Acoustic Signals Outside the Audible Frequency Range

• US 20070276658A1
• Filed: 05/23/2006
• Published: 11/29/2007
• Est. Priority Date: 05/23/2006
• Status: Abandoned Application

• Current Assignee: Barry Grayson Douglass
• Original Assignee: Barry Grayson Douglass
• Inventors: Douglass, Barry Grayson
• Application Number:
  US11/308,895
• Publication Number:
  US 20070276658A1
• Time in Patent Office: Days
• US Class Current: 704/205
• CPC Class Codes: G10L 15/26 Speech to text systems G10L15/08 takes precedence
• CPC Class Codes: G10L 21/0364 for improving intelligibility
• CPC Class Codes: G10L 25/78 Detection of presence or absence of voice signals switching of direction of transmission by voice frequency in two-way loud-speaking telephone systems H04M9/10

Abstract

The present invention employs sound generators, also known as acoustic transducers, which produce ultrasound or infrasound outside the normal human hearing range, placed in proximity to the vocal tract of the person whose speech is being detected, such as in front of the mouth. One or more microphones sensitive to these ultrasound or infrasound signals are also placed near the speaker'"'"'s vocal tract, to pick up the return signals from the speaker, which are modified by passage through and around the vocal tract as the person speaks. This invention overcomes the limitations of detecting speech by the traditional method of capturing normal voice acoustic signals. The added information from the infrasound or ultrasound signals creates a unique acoustic signature for each action of the vocal tract during speech, which can be used to improve the reliability of computer speech recognition and the quality of transmitted voice.

Claims

1. An apparatus for detecting speech comprising:

means for generating an acoustic signal outside the audible frequency range at the vocal tract of the person whose speech is being detected;

means for capturing the acoustic signal after it has interacted with the vocal tract of the person whose speech is being detected; and

means for detecting changes to the captured acoustic signal caused by speech.

2. An apparatus for detecting speech as in claim 1, wherein the means for generating an acoustic signal outside the audible frequency range comprises means for generating ultrasound.

3. An apparatus for detecting speech as in claim 1, wherein the means for generating an acoustic signal outside the audible frequency range comprises means for generating infrasound.

4. An apparatus for detecting speech as in claim 1, wherein the means for detecting changes to the captured acoustic signal comprises means for determining the phonemes being spoken by the person whose speech is being detected, by comparing the pattern of the captured acoustic signal to a database of speech patterns and their corresponding phonemes.

5. An apparatus for detecting speech as in claim 1, wherein the means for detecting changes to the captured acoustic signal comprises means for remodulating the captured acoustic signal to within the audible frequency range while preserving the speech signal modulation pattern.

6. An apparatus for detecting speech as in claim 1, wherein the means for generating an acoustic signal outside the audible frequency range comprises an acoustic transducer.

7. An apparatus for detecting speech as in claim 1, wherein the means for capturing the acoustic signal comprises a microphone.

8. A method for detecting speech comprising:

generating an acoustic signal outside the audible frequency range at the vocal tract of the person whose speech is being detected;

capturing the acoustic signal after it has interacted with the vocal tract of the person whose speech is being detected; and

processing the captured acoustic signal to detect changes to the signal caused by speech.

9. A method for detecting speech as in claim 8 wherein processing the captured acoustic signal to detect changes to the signal caused by speech comprises determining the phonemes being spoken by the person whose speech is being detected, by comparing the pattern of the captured acoustic signal to a database of speech patterns and their corresponding phonemes.

10. A method for detecting speech as in claim 8 wherein processing the captured acoustic signal to detect changes to the signal caused by speech comprises remodulating the captured acoustic signal to within the audible frequency range while preserving the speech signal modulation pattern.

11. A method for detecting speech as in claim 8 wherein generating an acoustic signal outside the audible frequency range comprises placing an acoustic transducer near the vocal tract.

12. A method for detecting speech as in claim 8 wherein capturing the acoustic signal after it has interacted with the vocal tract of the person whose speech is being detected comprises placing a microphone near the vocal tract.

13. A method for detecting speech as in claim 12 comprising placing a plurality of microphones advantageously arranged at positions around the vocal tract.

14. A method for detecting speech as in claim 11 comprising placing a plurality of acoustic transducers advantageously arranged at positions around the vocal tract.

15. A method for detecting speech as in claim 8 wherein generating an acoustic signal outside the audible frequency range comprises generating an acoustic signal outside the audible frequency range with a frequency spectrum which varies at intervals.

16. A method for detecting speech as in claim 8 wherein processing the captured acoustic signal to detect changes to the signal caused by speech comprises detecting time delay in the captured acoustic signal caused by speech.

17. A method for detecting speech as in claim 8 wherein generating an acoustic signal outside the audible frequency range comprises generating an acoustic signal outside the audible frequency range of varying strength at intervals.

18. A method for detecting speech as in claim 8 wherein generating an acoustic signal outside the audible frequency range comprises generating ultrasound.

19. A method for detecting speech as in claim 8 wherein generating an acoustic signal outside the audible frequency range comprises generating infrasound.

20. A method for detecting speech as in claim 8 wherein generating an acoustic signal outside the audible frequency range comprises generating a component of a sampled normal human voice which is remodulated to a frequency range outside the audible frequency range.