Abstract: Disclosed is an echo canceller including: a false echo calculator that calculates false echo signals by performing a filtering operation using each of current and previous filter-coefficient groups which used by an adaptive filtering unit on a sequence of reception signals (x(n)); an evaluation value calculator that calculates evaluated values of an echo cancellation quantity on the basis of a voice-transmission signal (y(n)) and the false echo signals; a false echo selector that selects an estimated echo component from the false echo components on the basis of the evaluated values of the echo cancellation quantity; and a signal output unit (Sout) that outputs a residual signal (e(n)).

Abstract: Disclosed is an echo canceller (10) including: a false echo calculator (32) that acquires current and previous filter-coefficient groups used by an adaptive filtering unit (20), and that calculates plural false echo signals by performing a filtering operation using each of the current and previous filter-coefficient groups on a sequence of reception signals (x(n)); a voice-transmission signal buffer that outputs a previous voice-transmission signal (y(n?1)); an evaluation value calculator (34) that calculates plural evaluated values of an echo cancellation quantity by using the previous voice-transmission signal; a filter selector (36) that selects a new filter-coefficient group on the basis of the plural evaluated values of the echo cancellation quantity; a foreground filter (39) that performs a filtering operation using the new filter-coefficient group on the sequence of reception signals (x(n)) to generate an estimated echo component; and a subtractor (25) that subtracts the estimated echo component from a

Abstract: An echo canceller device includes a band adjuster including a filter for performing band adjustment by applying a gain to a signal in a specific frequency band of an input signal, an adaptive filter for inputting a speech reception signal, updating a filter coefficient, and generating a pseudo echo signal using the updated filter coefficient, a band corrector including a filter for correcting a frequency characteristic of a signal obtained by subtracting the pseudo echo signal from an input signal, to a frequency characteristic of the input signal prior to the band adjustment, and a residual echo suppressor for suppressing an echo component that remains in a signal, by a suppression amount, and the residual echo suppressor sets the suppression amount for a signal in a specific frequency band that has been subjected to the band adjustment.

Abstract: An echo canceller device includes a band adjuster including a filter for performing band adjustment by applying a gain to a signal in a specific frequency band of an input signal, an adaptive filter for inputting a speech reception signal, updating a filter coefficient, and generating a pseudo echo signal using the updated filter coefficient, a band corrector including a filter for correcting a frequency characteristic of a signal obtained by subtracting the pseudo echo signal from an input signal, to a frequency characteristic of the input signal prior to the band adjustment, and a residual echo suppressor for suppressing an echo component that remains in a signal, by a suppression amount, and the residual echo suppressor sets the suppression amount for a signal in a specific frequency band that has been subjected to the band adjustment.

Abstract: A small-signal power acquisition unit defines a threshold for each of a plurality of input signals based on a long-term average of a minimum power of the corresponding input signal, each of the input signals being obtained by a microphone, sets a power value of each input signal that is smaller than the corresponding defined threshold to be a small-signal power of the input signal. A correction amount setting unit obtains each correction amount for correcting the input signals based on the small-signal power of the corresponding input signal. A correction unit corrects each of the input signals based on each of the correction amounts for correcting the input signals.

Abstract: An input signal analyzer determines a boundary frequency within the limit of a range which does not exceed a first frequency from the mode of an input signal. A spectrum compressor compresses a power spectrum of frequencies in a band higher than the first frequency in a frequency direction. A gain corrector performs a gain correction on the compressed power spectrum. A spectrum synthesizer reflects the power spectrum outputted from the gain corrector in a band determined by both the first frequency and the boundary frequency. A frequency-to-time converter converts both a synthesized power spectrum provided by the spectrum synthesizer and a phase spectrum of the input signal into ones in the time domain, and outputs these spectra.

Abstract: A small-signal power acquisition unit defines a threshold for each of a plurality of input signals based on a long-term average of a minimum power of the corresponding input signal, each of the input signals being obtained by a microphone, sets a power value of each input signal that is smaller than the corresponding defined threshold to be a small-signal power of the input signal. A correction amount setting unit obtains each correction amount for correcting the input signals based on the small-signal power of the corresponding input signal. A correction unit corrects each of the input signals based on each of the correction amounts for correcting the input signals.

Abstract: A sound source generating unit 101 generates from a narrowband audio signal not passing through noise suppression a sound source signal including a fine structure of a band to be restored. On the other hand, a noise suppressing unit 102 performs noise suppression of the narrowband audio signal and a spectral envelope estimating unit 103 estimates an spectral envelope of the band to be restored. A signal synthesizing unit 104 generates a pseudo-audio signal by combining the sound source signal and the spectral envelope, and the band-pass filter unit 105 passes the pseudo-audio signal of the band to be restored, and the signal addition unit 106 generates a broadband audio restoration signal by adding the pseudo-audio signal of the band to be restored to the narrowband audio signal.

Abstract: A noise suppression device includes an input signal analyzer that analyzes the harmonic structure and periodicity of a plurality of input signals on the basis of power spectra of a plurality of input signals, a power spectrum synthesizer that synthesizes the power spectra of the plurality of input signals to generate a synthesized power spectrum according to the result of the analysis by the input signal analyzer, a noise suppression amount calculator that calculates an amount of noise suppression on the basis of the synthesized power spectrum and an estimated noise spectrum estimated from the input signals, and a power spectrum suppressor that carries out noise suppression on the synthesized power spectrum by using the calculated amount of noise suppression.

Abstract: An input signal analyzer determines a boundary frequency within the limit of a range which does not exceed a first frequency from the mode of an input signal. A spectrum compressor compresses a power spectrum of frequencies in a band higher than the first frequency in a frequency direction. A gain corrector performs a gain correction on the compressed power spectrum. A spectrum synthesizer reflects the power spectrum outputted from the gain corrector in a band determined by both the first frequency and the boundary frequency. A frequency-to-time converter converts both a synthesized power spectrum provided by the spectrum synthesizer and a phase spectrum of the input signal into ones in the time domain, and outputs these spectra.

Abstract: A candidate voice segment sequence generator 1 generates candidate voice segment sequences 102 for an input language information sequence 101 by using DB voice segments 105 in a voice segment database 4. An output voice segment sequence determinator 2 calculates a degree of match between the input language information sequence 101 and each of the candidate voice segment sequences 102 by using a parameter 107 showing a value according to a cooccurrence criterion 106 for cooccurrence between the input language information sequence 101 and a sound parameter showing the attribute of each of a plurality of candidate voice segments in each of the candidate voice segment sequences 102, and determines an output voice segment sequence 103 on the basis of the degree of match.

Abstract: A candidate voice segment sequence generator 1 generates candidate voice segment sequences 102 for an input language information sequence 101 by using DB voice segments 105 in a voice segment database 4. An output voice segment sequence determinator 2 calculates a degree of match between the input language information sequence 101 and each of the candidate voice segment sequences 102 by using a parameter 107 showing a value according to a cooccurrence criterion 106 for cooccurrence between the input language information sequence 101 and a sound parameter showing the attribute of each of a plurality of candidate voice segments in each of the candidate voice segment sequences 102, and determines an output voice segment sequence 103 on the basis of the degree of match.

Abstract: A band separating unit 5 carries out a band division of a plurality of power spectra into which an input signal is converted by a time-to-frequency converting unit 2 to combine power spectra into each subband, and a band representative component generating unit 6 defines a power spectrum having a maximum among the plurality of power spectra within each subband as a representative power spectrum. A noise suppression amount generating unit 7 calculates an amount of noise suppression for each subband by using the representative power spectrum and a noise spectrum, and a noise suppressing unit 9 suppresses the amplitudes of the power spectra according to the amount of noise suppression.

Abstract: A probability density function controller determines a probability density function dependent upon whether an input signal appears to be a sound or noise, i.e., a probability density function that is suited to a distribution state of a sound signal in a sound section and that in a noise section, and a suppression amount calculator 8 calculates a spectrum suppression amount by using the probability density function.

Abstract: A sound source generating unit 101 generates from a narrowband audio signal not passing through noise suppression a sound source signal including a fine structure of a band to be restored. On the other hand, a noise suppressing unit 102 performs noise suppression of the narrowband audio signal and a spectral envelope estimating unit 103 estimates an spectral envelope of the band to be restored. A signal synthesizing unit 104 generates a pseudo-audio signal by combining the sound source signal and the spectral envelope, and the band-pass filter unit 105 passes the pseudo-audio signal of the band to be restored, and the signal addition unit 106 generates a broadband audio restoration signal by adding the pseudo-audio signal of the band to be restored to the narrowband audio signal.

Abstract: A noise suppression device includes: a power spectrum calculator converting an input signal of time domain into power spectra of frequency domain; a voice/noise determination unit determining whether the power spectra indicate voice or noise; a noise spectrum estimation unit estimating noise spectra of the power spectra; a period component estimation unit analyzing a harmonic structure constituting the power spectra and estimating periodical information about the power spectra; a weighting coefficient calculator calculating a weighting coefficient for weighting the power spectra; a suppression coefficient calculator calculating a suppression coefficient for suppressing noise included in the power spectra; a spectrum suppression unit suppressing amplitude of the power spectra in accordance with the suppression coefficient; and an inverse Fourier transformer converting the power spectra output by the spectrum suppression unit into a signal of time domain to generate a noise-suppressed signal.

Abstract: A noise suppressor selects, for individual frequency components, maximums by comparing a plurality of noise suppressed spectra 105 and 106 a plurality of noise suppressing units 4 and 5 output, thereby obtaining an output spectrum 107 having the frequency components selected as its components. A first noise suppressing unit 4 generates a noise suppressed spectrum 105 by multiplying an input spectrum 102 by amplitude suppression gains, and makes the amplitude suppression gains greater than most of the amplitude suppression gains in a noise signal intervals of a second noise suppressing unit 5.

Abstract: A correction spectrum calculation unit 6 obtains a correction spectrum by smoothing an estimated noise spectrum in accordance with the degree of its variations, and a suppression quantity limiting coefficient calculation unit 7 decides a suppression quantity limiting coefficient from the correction spectrum. A suppression quantity calculation unit 9 obtains a suppression coefficient based on the suppression quantity limiting coefficient, and the spectrum suppression unit 10 carries out amplitude suppression of spectral components of an input signal.

Abstract: A synthesis filter 106 synthesizes a plurality of wide-band speech signals by combining wide-band phoneme signals and sound source signals from a speech signal code book 105, and a distortion evaluation unit 107 selects one of the wide-band speech signals with a minimum waveform distortion with respect to an up-sampled narrow-band speech signal output from a sampling conversion unit 101. A first bandpass filter 103 extracts a frequency component outside a narrow-band of the wide-band speech signal and a band synthesis unit 104 combines it with the up-sampled narrow-band speech signal.

Abstract: Disclosed is a noise suppression device including an input signal analyzer 8 that analyzes the harmonic structure and periodicity of a plurality of input signals on the basis of the power spectra of the plurality of input signals, a power spectrum synthesizer 9 that synthesizes the power spectra of the plurality of input signals to generate a synthesized power spectrum according to the result of the analysis by the input signal analyzer 8, a noise suppression amount calculator 10 that calculates an amount of noise suppression on the basis of the synthesized power spectrum generated by the power spectrum synthesizer 9 and an estimated noise spectrum estimated from the input signals, and a power spectrum suppressor 11 that carries out noise suppression on the synthesized power spectrum generated by the power spectrum synthesizer 9 by using the amount of noise suppression calculated by the noise suppression amount calculator 10.