Formant frequency estimation method, apparatus, and medium in speech recognition
First Claim
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1. A formant frequency estimation method in speech recognition comprising:
- preprocessing an input speech signal and generating a spectrum by fast Fourier transforming the preprocessed input speech signal;
smoothing the generated spectrum;
accelerating the smoothed spectrum; and
determining a formant frequency on the basis of the accelerated spectrum.
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Abstract
A formant frequency estimation method which is important information in speech recognition by accelerating a spectrum using a pitch frequency, and an apparatus using the method is provided. That is, the formant frequency estimation method includes preprocessing an input speech signal and generating a spectrum by a fast Fourier transforming the preprocessed input speech signal; smoothing the generated spectrum; accelerating the smoothed spectrum; and determining a formant frequency on the basis of the accelerated spectrum.
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Citations
24 Claims
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1. A formant frequency estimation method in speech recognition comprising:
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preprocessing an input speech signal and generating a spectrum by fast Fourier transforming the preprocessed input speech signal; smoothing the generated spectrum; accelerating the smoothed spectrum; and determining a formant frequency on the basis of the accelerated spectrum. - View Dependent Claims (2, 3, 4, 5, 10)
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6. A formant frequency estimation method in speech recognition comprising:
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establishing a flag state backward; calculating an anchor parameter after preprocessing an input speech signal; executing buffering until the anchor parameter is above a predetermined threshold value; estimating a backward formant frequency after the anchor parameter is above the predetermined threshold value; and changing the flag state and establishing after estimating the backward formant frequency. - View Dependent Claims (7, 8, 9, 18)
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11. A formant frequency estimation apparatus in speech recognition comprising:
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a preprocess unit pre-processing an input speech signal; a fast Fourier transformation unit Fourier transforming the preprocessed input speech signal, and generating a spectrum; a smoothing unit smoothing the generated spectrum; an acceleration unit accelerating the smoothed spectrum; and a formant frequency determination unit determining a formant frequency on the basis of the accelerated spectrum. The apparatus of claim 11, wherein the formant frequency determining unit further comprises; a pitch frequency estimation unit estimating a pitch frequency of a preprocessed input speech signal, and wherein the smoothing unit is based on a moving average of the generated spectrum and smoothes the generated spectrum by using the number of tabs corresponding to the estimated pitch frequency. - View Dependent Claims (14)
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13. The apparatus of claim 12, wherein the acceleration unit calculates a first spectral difference corresponding to the smoothed spectrum, smoothes a spectrum of the first spectral difference, and calculates a second spectral difference corresponding to the spectrum the smoothed first spectral difference.
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15. A formant frequency estimation apparatus in speech recognition comprising:
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a flag state establishment unit establishing a flag state backward; an anchor parameter calculation unit calculating an anchor parameter after a preprocess of input speech signal; a buffering unit executing buffering until the anchor parameter is above a predetermined threshold value; a formant frequency estimation unit estimating a backward formant frequency after anchor parameter is above the predetermined threshold value; and wherein the flag state establishment unit changes and establishes the flag state after estimating the backward formant frequency. - View Dependent Claims (16, 17)
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19. A formant frequency estimation method in speech recognition comprising:
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calculating an anchor parameter from an input speech signal; executing buffering until the anchor parameter is above a predetermined threshold value; and estimating a backward formant frequency after the anchor parameter is above the predetermined threshold value. - View Dependent Claims (20, 21, 22, 23, 24)
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Specification