CLASSIFYING PORTIONS OF A SIGNAL REPRESENTING SPEECH

• US 20090271196A1
• Filed: 10/23/2008
• Published: 10/29/2009
• Est. Priority Date: 10/24/2007
• Status: Abandoned Application

• Current Assignee: Red Shift Company LLC
• Original Assignee: Red Shift Company LLC
• Inventors: Nyquist, Joel K., Remillard, John F., Reckase, Erik N., Robinson, Matthew D.
• Application Number:
  US12/256,729
• Publication Number:
  US 20090271196A1
• Time in Patent Office: Days
• US Class Current: 704/246
• CPC Class Codes: G10L 25/90 Pitch determination of speech signals
• CPC Class Codes: G10L 25/93 Discriminating between voiced and unvoiced parts of speech signals G10L25/90 takes precedence

Abstract

Methods, systems, and machine-readable media are disclosed for processing a signal representing speech. According to one embodiment, processing a signal representing speech can comprise receiving a frame of the signal representing speech. The frame can be classified as unvoiced or voiced based on occurrence of one or more events within the frame. For example, the one or more events can comprise one or more glottal pulses. In response to classifying the frame as voiced, the frame can be processed.

Claims

1. A method of processing a signal representing speech, the method comprising:

receiving a frame of the signal representing speech;

classifying the frame as unvoiced or voiced based on occurrence of one or more events within the frame; and

in response to classifying the frame as voiced, processing the frame.

2. The method of claim 1, wherein the one or more events comprise one or more glottal pulses.

3. The method of claim 1, wherein classifying the frame comprises:

determining a mean absolute value of an amplitude of the frame; and

in response to the mean absolute value of the amplitude of the frame not exceeding a threshold amount, classifying the frame as unvoiced.

4. The method of claim 3, further comprising, in response to the mean absolute value of the amplitude of the frame exceeding the threshold amount:

determining a maximum distance between zero crossing points in the frame;

in response to the maximum distance between zero crossing points in the frame exceeding a zero crossing threshold, classifying the frame as voiced, and

in response to the maximum distance between zero crossing points in the frame not exceeding a zero crossing threshold, classifying the frame as unvoiced.

5. The method of claim 3, further comprising, prior to classifying the frame as unvoiced or voiced, determining whether the frame includes detectable speech.

6. The method of claim 5, wherein determining whether the frame includes detectable speech is based on an amplitude of the signal in the frame.

7. The method of claim 5, wherein classifying the frame as unvoiced or voiced is performed in response to determining the frame includes detectable speech.

8. A system comprising:

an input device adapted to detect sound representing speech and convert the sound to an electrical signal representing the speech; and

a classification module communicatively coupled with the input device and adapted to receive a frame of the signal representing speech from the input device and classify the frame as unvoiced or voiced based on occurrence of one or more events within the frame.

9. The system of claim 8, wherein the one or more events comprise one or more glottal pulses.

10. The system of claim 8, wherein classifying the frame comprises:

determining a mean absolute value of an amplitude of the frame; and

in response to the mean absolute value of the amplitude of the frame not exceeding a threshold amount, classifying the frame as unvoiced.

11. The system of claim 10, wherein the classification module is further adapted to, in response to the mean absolute value of the amplitude of the frame exceeding the threshold amount, determine a maximum distance between zero crossing points in the frame, in response to the maximum distance between zero crossing points in the frame exceeding a zero crossing threshold, classify the frame as voiced, and in response to the maximum distance between zero crossing points in the frame not exceeding a zero crossing threshold, classifying the frame as unvoiced.

12. The system of claim 10, wherein the classification module is further adapted to, prior to classifying the frame as unvoiced or voiced, determine whether the frame includes detectable speech.

13. The system of claim 12, wherein determining whether the frame includes detectable speech is based on an amplitude of the signal in the frame.

14. The system of claim 12, wherein classifying the frame as unvoiced or voiced is performed in response to determining the frame includes detectable speech.

15. A machine-readable medium having stored thereon a series of instruction which, when executed by a processor, cause the processor to process a signal representing speech by:

receiving a frame of the signal representing speech;

classifying the frame as unvoiced or voiced based on occurrence of one or more events within the frame; and

in response to classifying the frame as voiced, processing the frame.

16. The method of claim 15, wherein the one or more events comprise one or more glottal pulses.

17. The machine-readable medium of claim 15, wherein classifying the frame comprises:

determining a mean absolute value of an amplitude of the frame; and

in response to the mean absolute value of the amplitude of the frame not exceeding a threshold amount, classifying the frame as unvoiced.

18. The machine-readable medium of claim 17, further comprising, in response to the mean absolute value of the amplitude of the frame exceeding the threshold amount:

determining a maximum distance between zero crossing points in the frame;

in response to the maximum distance between zero crossing points in the frame exceeding a zero crossing threshold, classifying the frame as voiced, and

in response to the maximum distance between zero crossing points in the frame not exceeding a zero crossing threshold, classifying the frame as unvoiced.

19. The machine-readable medium of claim 17, further comprising, prior to classifying the frame as unvoiced or voiced, determining whether the frame includes detectable speech.

20. The machine-readable medium of claim 19, wherein determining whether the frame includes detectable speech is based on an amplitude of the signal in the frame.

21. The machine-readable medium of claim 19, wherein classifying the frame as unvoiced or voiced is performed in response to determining the frame includes detectable speech.