Method and apparatus for processing speech signals

• US 20020138254A1
• Filed: 03/20/2002
• Published: 09/26/2002
• Est. Priority Date: 07/18/1997
• Status: Abandoned Application

• Current Assignee: Takehiko Isaka, Yoshifumi Nagata
• Original Assignee: Takehiko Isaka, Yoshifumi Nagata
• Inventors: Isaka, Takehiko, Nagata, Yoshifumi
• Application Number:
  US10/101,205
• Publication Number:
  US 20020138254A1
• Time in Patent Office: Days
• US Class Current: 704/208
• CPC Class Codes: G10L 2021/02161 Number of inputs available containing the signal or the noise to be suppressed
• CPC Class Codes: G10L 21/02 Speech enhancement, e.g. noise reduction or echo cancellation reducing echo effects in line transmission systems H04B3/20; echo suppression in hands-free telephones H04M9/08
• CPC Class Codes: G10L 25/93 Discriminating between voiced and unvoiced parts of speech signals G10L25/90 takes precedence

Abstract

A speech processing apparatus comprises a speech input section which receives multi-channel signals, a beam former processing section for performing beam former processing on the multi-channel signals to suppress a signal arriving from a target speech source, a target source direction estimation section for estimating the direction of the target source from filter coefficients resulting from the beam former processing, and a voiced/unvoiced speech determination section for determining a speech interval of a speech signal on the basis of the estimated direction of the target source.

Claims

1. A speech processing method comprising:

a speech signal inputting step of inputting a speech signal over a plurality of channels;

a beam former processing step of subjecting a beam former processing for suppressing a signal arriving from a target source with respect to the speech signal inputted by the speech signal inputting step;

a target source direction estimating step of estimating the direction of the target source from filter coefficients obtained by the beam former processing step; and

a speech interval determining step of determining a speech interval of the speech signal on the basis of the direction of the target source estimated by the target source direction estimating step.

2. The signal processing method according to claim 1, wherein the speech interval determining step determines the speech interval of the speech signal on the basis of the direction of the target source determined by the target source direction estimating step and the power of the speech signal.

3. A signal processing method comprising:

a speech signal inputting step of inputting a speech signal over a plurality of channels;

a first beam former processing step of performing beam former processing on the speech signal inputted by the speech signal inputting step to suppress a signal arriving from a target source;

a target source direction estimating step of estimating the direction of the target source from filter coefficients obtained by the first beam former processing step;

a second beam former processing step of subjecting a beam former processing to the speech signal inputted by the speech signal inputting step to suppress a signal arriving from a noise source and output the signal from the target source;

a noise source direction estimating step of estimating the direction of the noise source from filter coefficients obtained by the second beam former processing step;

a first control step of controlling the beam former processing by the second beam former processing step on the basis of the direction of the target source estimated by the target source direction estimating step and powers of outputs obtained by the first and second beam former processing steps;

a second control step of controlling the beam former processing by the first beam former processing step on the basis of the direction of the noise source estimated by the noise source direction estimating step and the powers of the outputs obtained by the first and second beam former processing steps; and

a speech interval determining step of determining a speech interval of the speech signal on the basis of the direction of the target source estimated by the target source direction estimating step.

4. The signal processing method according to claim 3, wherein the speech interval determining step determines the speech interval of the speech signal on the basis of the direction of the target source determined by the target source direction estimating step and the power of the speech signal.

5. A speech signal processing apparatus comprising:

a speech signal inputting section for inputting a speech signal over a plurality of channels;

a beam former for performing beam former processing on the speech signal inputted by the speech signal inputting section to suppress a signal arriving from a target source;

a target source direction estimating section for estimating the direction of the target source from filter coefficients obtained by the beam former processing section; and

a speech interval determining section for determining a speech interval of the speech signal on the basis of the direction of the target source estimated by the target source direction estimating section.

6. The signal processing apparatus according to claim 5, wherein the speech interval determining section determines the speech interval of the speech signal on the basis of the direction of the target source determined by the target source direction estimating section and the power of the speech signal.

7. A signal processing apparatus comprising:

a speech signal inputting section for inputting a speech signal over a plurality of channels;

a first beam former for performing beam former processing on the speech signal inputted by the speech signal inputting section to suppress a signal arriving from a target source;

a target source direction estimating section for estimating the direction of the target source from filter coefficients obtained by the first beam former processing section;

a second beam former processing section for performing beam former processing on the speech signal inputted by the speech signal inputting section to suppress a signal arriving from a noise source and output the signal from the target source;

a noise source direction estimating section for estimating the direction of the noise source from filter coefficients obtained by the second beam former processing section;

a first control section for controlling the second former on the basis of the direction of the target source estimated by the target source direction estimating section and powers of outputs obtained by the first and second beam formers;

a second control section for controlling the first beam former on the basis of the direction of the noise source estimated by the noise source direction estimating section and the powers of the outputs obtained by the first and second beam formers; and

a speech interval determining section for determining a speech interval of the speech signal on the basis of the direction of the target source estimated by the target source direction estimating section.

8. The signal processing apparatus according to claim 7, wherein the speech interval determining section determines the speech interval of the speech signal on the basis of the direction of the target source determined by the target source direction estimating section and the power of the speech signal.

9. A signal processing method comprising:

a speech signal inputting step of inputting a speech signal over a plurality of channels;

a first beam former processing step of performing beam former processing on the speech signal inputted by the speech signal inputting step to suppress a signal arriving from a target source;

a target source direction estimating step of estimating the direction of the target source from filter coefficients obtained by the first beam former processing step;

a second beam former processing step of performing beam former processing on the speech signal inputted by the speech signal inputting step to suppress a signal arriving from a noise source and output the signal from the target source;

a noise source direction estimating step of estimating the direction of the noise source from filter coefficients obtained by the second beam former processing step;

a first control step of controlling the second beam former processing step on the basis of the direction of the target source estimated by the target source direction estimating step and powers of outputs obtained by the first and second beam former processing steps;

a second control step of controlling the first beam former processing step on the basis of the direction of the noise source estimated by the noise source direction estimating step and the powers of the outputs obtained by the first and second beam former processing steps; and

a speech enhancement step of enhancing a speech signal by suppressing noise contained in the output signal obtained by the second beam former processing step on the basis of at least one of the output obtained by the first beam former processing step and the direction of the target source.

10. The speech processing method according to claim 9, further comprising a speech interval detecting step of detecting a speech interval of the speech signal on the basis of the direction of the target source estimated by the target source direction estimating step and the speech signal enhanced by the speech enhancement step.

11. A signal processing method comprising:

a speech signal inputting step of inputting a speech signal over a plurality of channels;

a first beam former processing step of performing beam former processing on the speech signal inputted by the speech signal inputting step to suppress a signal arriving from a target source;

a second beam former processing step of performing beam former processing on the speech signal inputted by the speech signal inputting step to suppress a signal arriving from a noise source and output the signal from the target source; and

a speech enhancement step of enhancing the speech signal by suppressing noise in the output obtained by the second beam former processing step on the basis of the output obtained by the first beam former processing step.

14. The speech processing apparatus according to claim 13, further comprising a speech interval detecting section for detecting a speech interval of the speech signal on the basis of the direction of the target source estimated by the target source direction estimating section and a signal having its speech component enhanced by the speech enhancing section.

18. The signal processing apparatus according to claim 17, further comprising an additional beam former having its input direction set to the middle of the input directions of the beam formers, an output signal of the additional beam former being obtained as a target signal.

19. The signal processing apparatus according to claim 17, wherein the input direction update section obtains the input direction updating information from response characteristics of the beam formers for their input directions computed from filter coefficients of filters in the beam formers.

20. The signal processing apparatus according to claim 17, wherein the input direction update section introduces a time delay in each of inputted multi-channel signals to set the input direction of each of the beam formers.

21. The signal processing apparatus according to claim 17, wherein the input direction update section obtains updating information representing new input directions of the beam formers by giving a small amount of change to the input directions prior to updating so as to make a shift in either of the input directions set in the beam formers.

12. A signal processing method comprising:

a speech signal inputting step of inputting a speech signal over a plurality of channels;

a beam former processing step of performing beam former processing on the speech signal inputted by the speech signal inputting step to suppress a signal arriving from a target source; and

a speech enhancement step of enhancing the speech signal by suppressing noise in a speech signal inputted over any of the plurality of channels on the basis of the output obtained by the first beam former processing step.

13. A signal processing apparatus comprising:

a speech signal inputting section for inputting a speech signal over a plurality of channels;

a first beam former for performing beam former processing on the speech signal inputted by the speech signal inputting section to suppress a signal arriving from a target source;

a target source direction estimating section for estimating the direction of the target source from filter coefficients obtained by the first beam former processing section;

a second beam former processing section for performing beam former processing on the speech signal inputted by the speech signal inputting section to suppress a signal arriving from a noise source and output the signal from the target source;

a noise source direction estimating section for estimating the direction of the noise source from filter coefficients obtained by the second beam former processing section;

a first control section for controlling the second former on the basis of the direction of the target source estimated by the target source direction estimating section and powers of outputs obtained by the first and second beam formers;

a second control section for controlling the first beam former on the basis of the direction of the noise source estimated by the noise source direction estimating section and the powers of the outputs obtained by the first and second beam formers; and

a speech enhancing section for enhancing a speech signal by suppressing noise in the output of the second beam former on the basis of at least one of the output of the first beam former and the direction of the target source estimated by the target source direction estimating section.

15. A signal processing apparatus comprising:

a speech signal inputting section for inputting a speech signal over a plurality of channels;

a first beam former for performing beam former processing on the speech signal inputted by the speech signal inputting section to suppress a signal arriving from a target source;

a second beam former for performing beam former processing on the speech signal inputted by the speech signal inputting section to suppress a signal arriving from a noise source and output the signal from the target source; and

a speech enhancing section for enhancing the speech signal by suppressing noise in the output of the second beam former on the basis of the output of the first beam former.

16. A signal processing method comprising:

a speech signal inputting section for inputting a speech signal over a plurality of channels;

a beam former performing beam former processing on the speech signal inputted by the speech signal inputting section to suppress a signal arriving from a target source; and

a speech enhancing section for enhancing the speech signal by suppressing noise in a speech signal inputted over any of the plurality of channels on the basis of the output of the first beam former.

17. A signal processing apparatus comprising:

a plurality of beam formers having their respective input directions set to different directions in advance and updated in accordance with updating information;

an input direction update section for, on the basis of outputs of the beam formers, detecting which of the input directions of the beam formers an actual signal arrival direction is closer to, seeking a quantity of correction for correcting the input directions of the beam formers in accordance with the detected result, changing the input directions of the beam formers by the quantity of correction to obtain new input directions as updating information, outputting the updating information to the beam formers, and repeating this processing; and

a reestablishing section for reestablishing the input directions of the beam formers to updated input directions.

22. A signal processing method comprising:

a step of setting each of target input directions of beam formers to a different direction;

a step of performing beam former processing in the beam formers;

an input direction updating step of detecting which of the input directions of the beam formers an actual signal arrival direction is closer to and computing new input directions of the beam formers; and

a step of reestablishing the input directions of the beam formers to updated input directions.

23. The signal processing method according to claim 22, further comprising a step of setting a direction which is the middle of the input directions of the beam formers as the input direction of an additional beam former and a step of performing beam former processing in the additional beam former, an output signal of the additional beam former being outputted as a target signal.

24. The signal processing method according to claim 22, wherein the input direction updating step updates the input direction of each of the beam formers on the basis of response characteristics for the input direction computed from its filter coefficients.

25. The signal processing method according to claim 22, wherein setting of the input directions in the beam formers is performed by introducing a time delay in each of the multi-channel signals.

26. The signal processing method according to claim 22, wherein the input direction updating step updates the input directions of the beam formers by giving a small amount of change to the input directions prior to updating so as to make a shift in either of the input directions set in the beam formers.