Abstract: A microphone generates a voice signal based on air vibration. A vibration sensor generates a vibration signal based on vibration transmitted to a human body. An adaptive filter multiplies the vibration signal by a coefficient to generate a converted voice signal. A subtractor generates a residual signal that is a difference between the voice signal and the converted voice signal. The adaptive controller controls the adaptive filter to update the coefficient so that the residual signal becomes small at a first speed when it is determined to be a voice section, and controls the adaptive filter to update the coefficient so that the residual signal becomes small at a second speed slower than the first speed when it is determined to be a non-audio section, or supplies the adaptive filter control signal to the adaptive filter to control not to update the coefficient.

Abstract: A frame signal generator is configured to generate a frame signal with a predetermined first time length from an input signal. A reference signal generator is configured to generate a reference signal from a signal located more in a past than a position of the frame signal in the input signal. A correlation value calculator is configured to calculate a correlation value between the frame signal and the reference signal within a range of a predetermined phase shift amount m. A periodic noise determiner is configured to determine whether or not the frame signal includes periodic noise, and calculate a period of the periodic noise in the case where the frame signal includes the periodic noise. A correlation value calculation range generator is configured to generate the range of the predetermined phase shift amount based on the period of the periodic noise.

Abstract: A frame generator 3 frames an input signal and generates a frame signal. A reference signal storage unit 7 stores therein a reference signal showing a periodic noise signal. A correlation value calculator 8 calculates a correlation value between the frame signal and the reference signal. A correlation candidate position decider 9 decides a plurality of correlation candidate positions serving as candidates for a signal portion of the reference signal correlated with the frame signal. A noise reduction processor 10 reduces a periodic noise signal, which is included in the frame signal, by using each signal portion of the plurality of correlation candidate positions, and generates a plurality of candidate output signals. An output signal decider 11 decides a candidate output signal, in which the periodic noise signal is reduced the most among the plurality of candidate output signals, and outputs the decided output signal.

Abstract: Provided is a noise signal suppressing device including: an input unit configured to receive a sound signal; a time/frequency converting unit; an independent peak spectrum extracting unit configured to extract a peak spectrum having independence; a persistence determining unit configured to determine that the peak spectrum having independence persists for a predetermined period or longer; a noise-signal suppressing unit configured to suppress the peak spectrum having independence as the noise signal. The independent peak spectrum extracting unit includes: a first peak extracting unit configured to extract a peak spectrum having higher energy than that of an adjacent frequency signal, and a second peak extracting unit configured to extract a peak spectrum maintaining a frequency interval of equal to or larger than a predetermined value with respect to a peak spectrum adjacent thereto as the peak spectrum having independence.

Abstract: A noise reduction apparatus according to the present invention includes: a sudden sound information storage unit that stores an input signal that are input before a current input signal is input as sudden sound information, the input signal having a signal level of voice components equal to or smaller than a predetermined threshold and including a sudden sound to be suppressed; a phase difference calculation unit that calculates a phase difference between the sudden sound information and a sudden sound in the current input signal based on a maximum value of a correlation value between the sudden sound information and the current input signal; an addition signal generation unit that shifts a phase of the sudden sound information based on the phase difference to generate an addition signal; and a sudden sound suppression unit that adds the addition signal and the current input signal to output an output signal.

Abstract: A frame generator 3 frames an input signal and generates a frame signal. A reference signal storage unit 7 stores therein a reference signal showing a periodic noise signal. A correlation value calculator 8 calculates a correlation value between the frame signal and the reference signal. A correlation candidate position decider 9 decides a plurality of correlation candidate positions serving as candidates for a signal portion of the reference signal correlated with the frame signal. A noise reduction processor 10 reduces a periodic noise signal, which is included in the frame signal, by using each signal portion of the plurality of correlation candidate positions, and generates a plurality of candidate output signals. An output signal decider 11 decides a candidate output signal, in which the periodic noise signal is reduced the most among the plurality of candidate output signals, and outputs the decided output signal.

Abstract: A frame signal generator is configured to generate a frame signal with a predetermined first time length from an input signal. A reference signal generator is configured to generate a reference signal from a signal located more in a past than a position of the frame signal in the input signal. A correlation value calculator is configured to calculate a correlation value between the frame signal and the reference signal within a range of a predetermined phase shift amount m. A periodic noise determiner is configured to determine whether or not the frame signal includes periodic noise, and calculate a period of the periodic noise in the case where the frame signal includes the periodic noise. A correlation value calculation range generator is configured to generate the range of the predetermined phase shift amount based on the period of the periodic noise.

Abstract: A noise elimination device according to the present invention includes a signal separation unit that divides input frequency information generated from an input signal on a time-domain into suppression target band information including a cyclic noise as the main component and intended sound band information including intended sound band information as the main component, a first frequency reverse-conversion unit that converts the suppression target band information into time-domain information and thereby outputs a suppression target signal, a second frequency reverse-conversion unit that converts the intended sound band information into time-domain information and thereby outputs an intended sound signal, and a cyclic noise information storage unit that accumulates the suppression target signal and thereby stores noise history information including information corresponding to at least one cycle of the cyclic noise.

Abstract: A noise reduction apparatus according to the present invention includes: a sudden sound information storage unit that stores an input signal that are input before a current input signal is input as sudden sound information, the input signal having a signal level of voice components equal to or smaller than a predetermined threshold and including a sudden sound to be suppressed; a phase difference calculation unit that calculates a phase difference between the sudden sound information and a sudden sound in the current input signal based on a maximum value of a correlation value between the sudden sound information and the current input signal; an addition signal generation unit that shifts a phase of the sudden sound information based on the phase difference to generate an addition signal; and a sudden sound suppression unit that adds the addition signal and the current input signal to output an output signal.

Abstract: A noise elimination device according to the present invention includes a periodic noise information storage unit 32 configured to accumulates an input signal including a periodic noise, and thereby stores noise history information which includes at least one cycle of the periodic noise in a non-voice section in which a voice signal component is equal to or lower than a predetermined voice threshold level, wherein the voice signal component is being a main component of an output signal, and a noise filter 35 that generates a suppression signal in which the periodic noise included in the input signal is reversed by using the noise history information as a reference signal, and generates the output signal So in which the periodic noise included in the input signal is suppressed by using the suppression signal.

Abstract: A noise elimination device according to the present invention includes a signal separation unit that divides input frequency information generated from an input signal on a time-domain into suppression target band information including a cyclic noise as the main component and intended sound band information including intended sound band information as the main component, a first frequency reverse-conversion unit that converts the suppression target band information into time-domain information and thereby outputs a suppression target signal, a second frequency reverse-conversion unit that converts the intended sound band information into time-domain information and thereby outputs an intended sound signal, and a cyclic noise information storage unit that accumulates the suppression target signal and thereby stores noise history information including information corresponding to at least one cycle of the cyclic noise.

Abstract: A signal portion per frame is extracted from an input signal, thus generating a per-frame signal. The per-frame signal in the time domain is converted into a per-frame signal in the frequency domain, thereby generating a spectral pattern of spectra. It is determined whether an energy ratio is higher than a threshold level. The energy ratio is a ratio of each spectral energy to subband energy in a subband that involves the spectrum. The subband is involved in subbands into which a frequency band is separated with a specific bandwidth. It is determined whether the per-frame signal is a speech segment, based on a result of the determination. Average energy is derived in the frequency direction for the spectra in the spectral pattern in each subband. Subband energy is derived per subband by averaging the average energy in the time domain.

Abstract: It is determined whether or not a sound picked up by at least either a first microphone or a second microphone is a speech segment. When it is determined that the sound picked up by the first or the second microphone is the speech segment, a voice incoming direction indicating from which direction a voice sound travels is detected based on a first sound pick-up signal obtained based on a sound picked up by the first microphone and a second sound pick-up signal obtained based on a sound picked up by the second microphone. A noise reduction process is performed using the first and second sound pick-up signals based on speech segment information indicating that the sound picked up by the first or the second microphone is the speech segment and voice incoming-direction information indicating the voice incoming direction.

Abstract: Provided is a noise signal suppressing device including: an input unit configured to receive a sound signal; a time/frequency converting unit; an independent peak spectrum extracting unit configured to extract a peak spectrum having independence; a persistence determining unit configured to determine that the peak spectrum having independence persists for a predetermined period or longer; a noise-signal suppressing unit configured to suppress the peak spectrum having independence as the noise signal. The independent peak spectrum extracting unit includes: a first peak extracting unit configured to extract a peak spectrum having higher energy than that of an adjacent frequency signal, and a second peak extracting unit configured to extract a peak spectrum maintaining a frequency interval of equal to or larger than a predetermined value with respect to a peak spectrum adjacent thereto as the peak spectrum having independence.

Abstract: A signal portion is extracted per frame having a specific duration from an input signal, thus generating a per-frame input signal. The per-frame input signal in the time domain is converted into a per-frame input signal in the frequency domain, thereby generating a spectral pattern of spectra. Peak spectra having peaks are detected in the spectral pattern. A harmonic spectrum is determined, in the peak spectra, having a harmonic structure showing a relationship between a fundamental pitch and a harmonic overtone.

Abstract: A signal portion is extracted from an input signal for each frame having a specific duration to generate a per-frame input signal. The per-frame input signal in a time domain is converted into a per-frame input signal in a frequency domain, thereby generating a spectral pattern. Subband average energy is derived in each of subbands adjacent one another in the spectral pattern. The subband average energy is compared in at least one subband pair of a first subband and a second subband that is a higher frequency band than the first subband, the first and second subbands being consecutive subbands in the spectral pattern. It is determined that the per-frame input signal includes a consonant segment if the subband average energy of the second subband is higher than the subband average energy of the first subband.

Abstract: It is determined whether or not a sound picked up by at least either a first microphone or a second microphone is a speech segment. When it is determined that the sound picked up by the first or the second microphone is the speech segment, a voice incoming direction indicating from which direction a voice sound travels is detected based on a first sound pick-up signal obtained based on a sound picked up by the first microphone and a second sound pick-up signal obtained based on a sound picked up by the second microphone. A noise reduction process is performed using the first and second sound pick-up signals based on speech segment information indicating that the sound picked up by the first or the second microphone is the speech segment and voice incoming-direction information indicating the voice incoming direction.

Abstract: In frequency signals obtained by converting input audio signals from time-domain signals to frequency-domain signals, a level control value setting unit 5 establishes a level control value for reducing the levels of spectrums at a noise-components level. A level control value smoothing unit 6 carries out a smoothing process of smoothing the level control value established by the level control value setting unit 5 temporally. A spectral adjustment unit 8 multiplies the level control value after the smoothing process by the frequency signals, performing a level control.

Abstract: A signal portion is extracted from an input signal for each frame having a specific duration to generate a per-frame input signal. The per-frame input signal in a time domain is converted into a per-frame input signal in a frequency domain, thereby generating a spectral pattern. Subband average energy is derived in each of subbands adjacent one another in the spectral pattern. The subband average energy is compared in at least one subband pair of a first subband and a second subband that is a higher frequency band than the first subband, the first and second subbands being consecutive subbands in the spectral pattern. It is determined that the per-frame input signal includes a consonant segment if the subband average energy of the second subband is higher than the subband average energy of the first subband.

Abstract: A signal portion is extracted per frame having a specific duration from an input signal, thus generating a per-frame input signal. The per-frame input signal in the time domain is converted into a per-frame input signal in the frequency domain, thereby generating a spectral pattern of spectra. Peak spectra having peaks are detected in the spectral pattern. A harmonic spectrum is determined, in the peak spectra, having a harmonic structure showing a relationship between a fundamental pitch and a harmonic overtone.