Voice detection apparatus
First Claim
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1. A voice detection apparatus comprising:
- signal power calculation means for receiving an input voice signal that comprises a plurality of frames and has voiced and silent intervals and for calculating a signal power of the input voice signal for each of the frames;
zero crossing counting means for counting a number of polarity inversions of the input voice signal for each of the frames;
adaptive prediction filter means for obtaining a prediction error signal of the input voice signal for each of the frames;
error signal power calculation means for calculating an error signal power of the prediction error signal for each of the frames;
power comparing means for comparing the signal power of the input voice signal and the error signal power of the prediction error signal and for obtaining a power ratio responsive to the comparing; and
discriminating means for discriminating the voiced and silent intervals based on the signal power, the counted number of polarity inversions and the power ratio,said discriminating means including;
first means for discriminating the voiced and silent intervals of the input voice signal based on the counted number of polarity inversions, andsecond means for determining an absolute value of a difference of the power ratios between the frames, and for discriminating whether a frame is a voiced interval or a silent interval depending on a comparison of the absolute value with a first threshold value and whether a previous frame is a voiced interval or a silent interval when the signal power of the input voice signal is less than a second threshold value.
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Abstract
Speech presence versus silence is decided by a discriminator which can use a certain combination of parameter values: signal power, prediction error power, prediction error power deviation, and zero crossings.
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Citations
19 Claims
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1. A voice detection apparatus comprising:
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signal power calculation means for receiving an input voice signal that comprises a plurality of frames and has voiced and silent intervals and for calculating a signal power of the input voice signal for each of the frames; zero crossing counting means for counting a number of polarity inversions of the input voice signal for each of the frames; adaptive prediction filter means for obtaining a prediction error signal of the input voice signal for each of the frames; error signal power calculation means for calculating an error signal power of the prediction error signal for each of the frames; power comparing means for comparing the signal power of the input voice signal and the error signal power of the prediction error signal and for obtaining a power ratio responsive to the comparing; and discriminating means for discriminating the voiced and silent intervals based on the signal power, the counted number of polarity inversions and the power ratio, said discriminating means including; first means for discriminating the voiced and silent intervals of the input voice signal based on the counted number of polarity inversions, and second means for determining an absolute value of a difference of the power ratios between the frames, and for discriminating whether a frame is a voiced interval or a silent interval depending on a comparison of the absolute value with a first threshold value and whether a previous frame is a voiced interval or a silent interval when the signal power of the input voice signal is less than a second threshold value. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A voice detection apparatus comprising:
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signal power calculation means for receiving an input voice signal that comprises a plurality of frames and has voiced and silent intervals and for calculating a signal power of the input voice signal for each of the frames; zero crossing counting means for counting a number of polarity inversions of the input voice signal for each of the frames; prediction gain deviation calculation means for calculating a prediction gain and a prediction gain deviation between frames based on the input voice signal and the signal power calculated in said signal power calculation means; and discriminating means for discriminating the voiced and the silent intervals based on the signal power, the counted number of polarity inversions and the prediction gain and the prediction gain deviation, said discriminating means including; first means for discriminating the voiced and silent intervals of the input voice signal based on when the signal power is greater than or equal to a first threshold value and the counted number of polarity inversions falls outside a predetermined range of a second threshold value, and second means for discriminating the voiced and silent intervals of the voice signal based on a comparison of the prediction gain deviation and a third threshold value when the signal power is less than the first threshold value and the counted number of polarity inversions falls within the predetermined range of the second threshold value. - View Dependent Claims (9, 10, 11, 17, 18, 19)
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12. A voice detection apparatus for detecting voiced and silent intervals of an input voice signal that comprises a plurality of frames and has voiced and silent intervals, said voice detection apparatus comprising:
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prediction gain detection means for receiving the input voice signal and for detecting a prediction gain for a frame of the input voice signal; prediction gain deviation detection means for receiving the input voice signal and for detecting a prediction gain deviation between frames; and discriminating means for performing a first comparison of the prediction gain with a first threshold value and a second comparison of the prediction gain deviation with a second threshold value and for discriminating whether one of the frames of the input voice signal is a voiced interval or a silent interval based on the first and second comparisons. - View Dependent Claims (13, 14, 15, 16)
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Specification