Voiced/unvoiced information estimation system and method therefor
First Claim
1. A method of estimating voiced/unvoiced information from a voice input signal, the method comprising:
- transforming the voice input signal into an input spectrum having input spectrum energy;
calculating a synthetic spectrum having synthetic spectrum energy using at least one of a fundamental frequency, a harmonic size and a window spectrum;
determining at least one voice level decision band from the input spectrum and the synthetic spectrum;
determining a band spectral difference energy for the at least one voice level decision band by finding the difference between the input spectrum energy and the synthetic spectrum energy;
normalizing the band spectral difference energy with the input spectrum energy to determine a normalized spectra difference energy; and
calculating a voicing level corresponding to the at least one voice level decision band using the normalized spectra difference energy, the voicing level calculated without utilizing a threshold such that a mixture of a voiced element and an unvoiced element are represented.
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Abstract
A voiced/unvoiced information estimation system uses input spectrum and synthetic spectrum to produce a voicing level spectrum. The estimation system uses a spectrum difference calculation unit to normalize a spectrum difference energy for each harmonic band in unit of harmonic band, and further uses a voicing level calculation unit to calculate a voicing level. The voicing level of each harmonic band has a continuous value between 1 and 0. The estimation system is effective in vector quantization of voiced/unvoiced information at a low bit rate. Because it is unnecessary to calculate a threshold for deciding a voiced/unvoiced information, a decision anomaly occurring due to threshold is eliminated, and the accuracy of a voicing level is improved. Furthermore, since a spectrum is represented by mixing a voiced element and a unvoiced element in a harmonic band, the estimation system improves the audio quality of a combined sound.
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Citations
20 Claims
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1. A method of estimating voiced/unvoiced information from a voice input signal, the method comprising:
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transforming the voice input signal into an input spectrum having input spectrum energy; calculating a synthetic spectrum having synthetic spectrum energy using at least one of a fundamental frequency, a harmonic size and a window spectrum; determining at least one voice level decision band from the input spectrum and the synthetic spectrum; determining a band spectral difference energy for the at least one voice level decision band by finding the difference between the input spectrum energy and the synthetic spectrum energy; normalizing the band spectral difference energy with the input spectrum energy to determine a normalized spectra difference energy; and calculating a voicing level corresponding to the at least one voice level decision band using the normalized spectra difference energy, the voicing level calculated without utilizing a threshold such that a mixture of a voiced element and an unvoiced element are represented. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method of estimating voiced/unvoiced information from a voice input signal, the method comprising:
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transforming the voice input signal into an input spectrum having input spectrum energy; obtaining a synthetic spectrum having synthetic spectrum energy using at least one of a fundamental frequency, a harmonic size and a window spectrum; determining L voice level decision bands from the input spectrum and the synthetic spectrum, wherein L is an integer; determining a corresponding band spectral difference energy for each voice level decision band by finding the difference between the respective input spectrum energy and the respective synthetic spectrum energy; normalizing the band spectral difference energy with the input spectrum energy to determine a normalized spectra difference energy for each voice level decision band; and calculating a voicing level corresponding to the each voice level decision band using the normalized spectra difference energy, the voicing level calculated without utilizing a threshold such that a mixture of a voiced element and an unvoiced element are represented. - View Dependent Claims (8, 9, 10)
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11. An estimation system for estimating voiced/unvoiced information from a voice input signal, the estimation system comprising:
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means for transforming the voice input signal into an input spectrum having input spectrum energy; means for obtaining a synthetic spectrum having synthetic spectrum energy using at least one of a fundamental frequency, a harmonic size and a window spectrum; means for determining at least one voice level decision band from the input spectrum and the synthetic spectrum; means for determining a band spectral difference energy for the at least one voice level decision band by finding the difference between the input spectrum energy and the synthetic spectrum energy; means for normalizing the band spectral difference energy with the input spectrum energy to determine a normalized spectra difference energy; and means for calculating a voicing level corresponding to the at least one voice level decision band using the normalized spectra difference energy, the voicing level calculated without utilizing a threshold such that a mixture of a voiced element and an unvoiced element are represented. - View Dependent Claims (12, 13, 14, 15, 16)
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17. An estimation system for estimating voiced/unvoiced information from a voice input signal, the estimation system comprising:
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means for transforming the voice input signal into an input spectrum having input spectrum energy; means for obtaining a synthetic spectrum having synthetic spectrum energy using at least one of a fundamental frequency, a harmonic size and a window spectrum; a spectrum difference calculation unit to determine at least one voice level decision band from the input spectrum and the synthetic spectrum and to determine a band spectral difference energy for the at least one voice level decision band by finding difference between the input spectrum energy and the synthetic spectrum energy and normalizing the band spectral difference energy with the input spectrum energy to determine a normalized spectra difference energy; and a voicing level calculation unit to calculate a voicing level corresponding to the at least one voice level decision band using the normalized spectra difference energy, the voicing level calculated without utilizing a threshold such that a mixture of a voiced element and an unvoiced element are represented. - View Dependent Claims (18, 19, 20)
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Specification