Sound signal processing apparatus and degree of speech computation method

• US 20060004568A1
• Filed: 06/30/2005
• Published: 01/05/2006
• Est. Priority Date: 06/30/2004
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Kondo, Tetsujiro, Ichiki, Hiroshi, Shima, Junichi, Arimitsu, Akihiko
• Granted Patent: US 7,555,429 B2
• Time in Patent Office: Days
• US Class Current: 704/210
• 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

Speech likeliness or a degree of speech is determined with a simple configuration or with a small amount of processing, and speech parts are separated from an input sound signal. The input sound signal is subjected to a waveform slicing process in frame units. The increase and decrease rate of a half wavelength in the frame is computed. The rate of a zero cross in the frame is computed. The increase and decrease rate of a half wavelength is computed by determining the rate of the portion where the upward half-wavelength or the downward half-wavelength of the waveform of the input sound signal changes to increase and decrease alternately or to decrease and increase alternately. The degree of speech is determined using each rate. Speech processing for separating or accentuating/attenuating speech and background noise in accordance with the degree of speech is performed on the sound signal for each frame.

Claims

1. A processor-implemented sound signal processing apparatus comprising:

a degree of vocally generated sound computation mechanism configured to compute and output an indicia of a degree of vocally generated sound of a sound signal input thereto, said sound signal including a vocally generated sound and ambient sound; and

a voice processor configured to characterize the input sound signal based on the indicia of degree of vocally generated sound output by the degree of vocally generated sound computation mechanism,

wherein the degree of vocally generated sound computation mechanism is configured to compute the indicia of degree of vocally generated sound based on features in a wavelength direction of a waveform of the input sound signal.

2. The apparatus of claim 1, wherein:

said degree of vocally generated sound computation mechanism includes a degree of speech computation mechanism;

said vocally generated sound is speech; and

said voice processor is configured to characterize the input sound signal based on the degree of speech in said sound signal as determined by said degree of vocally generated sound computation mechanism.

3. The sound signal processing apparatus according to claim 2, wherein the features in the wavelength direction are changes in a duration of a period of waveform of the sound signal.

4. The sound signal processing apparatus according to claim 2, wherein the features in the wavelength direction are changes in a level direction of the waveform of the sound signal.

5. The sound signal processing apparatus according to claim 2, wherein the degree of speech computation mechanism is configured to compute the degree of speech in units of frames sliced in predetermined time length units of the sound signal.

6. The sound signal processing apparatus according to claim 2, wherein the degree of speech computation mechanism comprises:

a half-wavelength increase and decrease repetition rate computation mechanism configured to compute an increase and a decrease in repetition rate of half wavelengths of a waveform of the sound signal;

a zero-cross rate computation mechanism configured to compute a rate of zero crossings of half wavelengths of the waveform of the sound signal; and

a degree of vocally generated sound output mechanism configured to output the indicia of degree of vocally generated sound on the basis of an output from the half-wavelength increase and decrease repetition rate computation mechanism and an output from the zero-cross rate computation mechanism.

7. The sound signal processing apparatus according to claim 6, wherein the half-wavelength increase and decrease repetition rate computation mechanism is configured to compute the increase and decrease repetition rate of the half wavelength of the waveform based on a rate of a portion of the waveform where an upward half-wavelength of the waveform of the sound signal changes so as to increase and decrease alternately or changes so as to decrease and increase alternately, and based on a rate of a portion where a downward half-wavelength of the waveform of the sound signal changes so as to increase and decrease alternately or changes so as to decrease and increase alternately.

8. The sound signal processing apparatus according to claim 6, wherein the half-wavelength increase and decrease repetition rate computation mechanism includes a first output value adjustment mechanism configured to adjust the repetition rate of the half wavelengths produced by the half-wavelength increase and decrease repetition rate computation mechanism,

the zero-cross rate computation mechanism includes a second output value adjustment mechanism configured to adjust the rate of zero-crossings produced by said zero-cross rate computation mechanism, and

the first and second output value adjustment mechanisms are configured to adjust and provide respective output values to the degree of vocally generated sound output mechanism.

9. The sound signal processing apparatus according to claim 2, further comprising:

a band dividing mechanism configured to divide the sound signal into a plurality of frequency bands, wherein the degree of vocally generated sound computation mechanism is configured to compute the indicia of degree of vocally generated sound for each band, and the voice processor is configured to process each band on the basis of the computed degree of vocally generated sound of each band.

10. A method for computing an indicia of degree of vocally generated sound, comprising steps of:

slicing a waveform of an input sound signal in units of frames of a predetermined length;

computing and outputting the indicia of a degree of vocally generated sound of a sound signal input thereto, said sound signal including a vocally generated sound and ambient sound; and

characterizing the input sound signal based on the indicia of degree of vocally generated sound;

wherein said computing step includes computing the indicia of degree of vocally generated sound based on features in a wavelength direction of a waveform of the input sound signal.

11. The method of claim 10 further comprising steps of:

computing an increase and decrease repetition rate of half wavelengths of the waveform sliced in the slicing step;

computing a rate of the zero cross of the half wavelengths of the waveform sliced in the slicing step; and

determining and outputting the indicia of degree of vocally generated sound on the basis of an output from the computing an increase and decrease repetition rate step and computing a rate of zero cross step.

12. The method according of claim 11, wherein:

in the computing an increase and decrease step, the increase and decrease repetition rate of the half wavelength is computed on the basis of a rate of a portion of the signal where an upward half-wavelength of the waveform changes so as to increase and decrease alternately or changes so as to decrease and increase alternately and on the basis of the rate of the portion where a downward half-wavelength of the waveform changes so as to increase and decrease alternately or changes so as to decrease and increase alternately.

13. The method of claim 11, wherein:

the calculating an increase and decrease step includes adjusting the repetition rate of half wavelengths, and the computing a rate of zero cross rate includes adjusting the rate of zero-crossings.

14. The method of claim 10, further comprising:

dividing the sound signal into a plurality of frequency bands, and

computing the indicia of degree of vocally generated sound for each band.

15. A computer program product having computer readable instructions that when executed by a processor implement a processing comprising steps of:

slicing a waveform of an input sound signal in units of frames of a predetermined length;

computing and outputting the indicia of a degree of vocally generated sound of a sound signal input thereto, said sound signal including a vocally generated sound and ambient sound; and

characterizing the input sound signal based on the indicia of degree of vocally generated sound;

wherein

said computing step includes computing the indicia of degree of vocally generated sound based on features in a wavelength direction of a waveform of the input sound signal.

16. The computer program product of claim 15, further comprising:

computing an increase and decrease repetition rate of half wavelengths of the waveform sliced in the slicing step;

computing a rate of the zero cross of the half wavelengths of the waveform sliced in the slicing step; and

determining and outputting the indicia of degree of vocally generated sound on the basis of an output from the computing an increase and decrease repetition rate step and computing a rate of zero cross step.

17. The computer program product of claim 16, wherein:

in the computing an increase and decrease step, the increase and decrease repetition rate of the half wavelength is computed on the basis of a rate of a portion of the signal where an upward half-wavelength of the waveform changes so as to increase and decrease alternately or changes so as to decrease and increase alternately and on the basis of the rate of the portion where a downward half-wavelength of the waveform changes so as to increase and decrease alternately or changes so as to decrease and increase alternately.

18. The computer program product of claim 16, wherein:

the calculating an increase and decrease step includes adjusting the repetition rate of half wavelengths, and

the computing a rate of zero cross rate includes adjusting the rate of zero-crossings.

19. The computer program product of claim 15, further comprising:

dividing the sound signal into a plurality of frequency bands, and

computing the indicia of degree of vocally generated sound for each band.

20. A processor-implemented sound signal processing apparatus comprising:

means for slicing a waveform of an input sound signal in units of frames of a predetermined length;

means for computing and outputting an indicia of a degree of vocally generated sound of a sound signal input thereto from the means for slicing, said sound signal including a vocally generated sound and ambient sound; and

means for characterizing the input sound signal based on the indicia of degree of vocally generated sound;

wherein

said means for computing includes means for calculating the indicia of degree of vocally generated sound based on features in a wavelength direction of a waveform of the input sound signal.