Abstract: A noise estimation apparatus which estimates a non-stationary noise component on the basis of the likelihood maximization criterion is provided. The noise estimation apparatus obtains the variance of a noise signal that causes a large value to be obtained by weighted addition of the sums each of which is obtained by adding the product of the log likelihood of a model of an observed signal expressed by a Gaussian distribution in a speech segment and a speech posterior probability in each frame, and the product of the log likelihood of a model of an observed signal expressed by a Gaussian distribution in a non-speech segment and a non-speech posterior probability in each frame, by using complex spectra of a plurality of observed signals up to the current frame.

Abstract: A noise estimation apparatus which estimates a non-stationary noise component on the basis of the likelihood maximization criterion is provided. The noise estimation apparatus obtains the variance of a noise signal that causes a large value to be obtained by weighted addition of the sums each of which is obtained by adding the product of the log likelihood of a model of an observed signal expressed by a Gaussian distribution in a speech segment and a speech posterior probability in each frame, and the product of the log likelihood of a model of an observed signal expressed by a Gaussian distribution in a non-speech segment and a non-speech posterior probability in each frame, by using complex spectra of a plurality of observed signals up to the current frame.

Abstract: The initial values of parameter estimates are set, including reverberation parameter estimates, which includes a regression coefficient used in a linear convolutional operation for calculating an estimated value of reverberation included in an observed signal, source parameter estimates, which includes estimated values of a linear prediction coefficient and a prediction residual power that identify the power spectrum of a source signal, and noise parameter estimates, which include noise power spectrum estimates. Then, the maximum likelihood estimation is used to alternately repeat processing for updating at least one of the reverberation parameter estimates and the noise parameter estimates and processing for updating the source parameter estimates until a predetermined termination condition is satisfied.

Abstract: Provided is a signal distortion elimination apparatus comprising: an inverse filter application means that outputs the signal obtained by applying an inverse filter to an observed signal as a restored signal when a predetermined iteration termination condition is met and outputs the signal obtained by applying the inverse filter to the observed signal as an ad-hoc signal when the predetermined iteration termination condition is not met; a prediction error filter calculation means that segments the ad-hoc signal into frames and outputs a prediction error filter of each frame obtained by performing linear prediction analysis of the ad-hoc signal of each frame; an inverse filter calculation means that calculates an inverse filter such that a concatenation of innovation estimates of the respective frames becomes mutually independent among their samples, where the innovation estimate of a single frame (an innovation estimate) is the signal obtained by applying the prediction error filter of the corresponding frame

Abstract: A sound source model storage section stores a sound source model that represents an audio signal emitted from a sound source in the form of a probability density function. An observation signal, which is obtained by collecting the audio signal, is converted into a plurality of frequency-specific observation signals each corresponding to one of a plurality of frequency bands. Then, a dereverberation filter corresponding to each frequency band is estimated by using the frequency-specific observation signal for the frequency band on the basis of the sound source model and a reverberation model that represents a relationship for each frequency band among the audio signal, the observation signal and the dereverberation filter. A frequency-specific target signal corresponding to each frequency band is determined by applying the dereverberation filter for the frequency band to the frequency-specific observation signal for the frequency band, and the resulting frequency-specific target signals are integrated.

Abstract: The initial values of parameter estimates are set, including reverberation parameter estimates, which includes a regression coefficient used in a linear convolutional operation for calculating an estimated value of reverberation included in an observed signal, source parameter estimates, which includes estimated values of a linear prediction coefficient and a prediction residual power that identify the power spectrum of a source signal, and noise parameter estimates, which include noise power spectrum estimates. Then, the maximum likelihood estimation is used to alternately repeat processing for updating at least one of the reverberation parameter estimates and the noise parameter estimates and processing for updating the source parameter estimates until a predetermined termination condition is satisfied.

Abstract: A sound source model storage section stores a sound source model that represents an audio signal emitted from a sound source in the form of a probability density function. An observation signal, which is obtained by collecting the audio signal, is converted into a plurality of frequency-specific observation signals each corresponding to one of a plurality of frequency bands. Then, a dereverberation filter corresponding to each frequency band is estimated by using the frequency-specific observation signal for the frequency band on the basis of the sound source model and a reverberation model that represents a relationship for each frequency band among the audio signal, the observation signal and the dereverberation filter. A frequency-specific target signal corresponding to each frequency band is determined by applying the dereverberation filter for the frequency band to the frequency-specific observation signal for the frequency band, and the resulting frequency-specific target signals are integrated.

Abstract: An aqueous dispersion type fluorine-containing water- and oil-repellent composition containing a polymer of a perfluoroalkyl group-containing ethylenically unsaturated monomer dispersed in an aqueous medium. The composition also contains a nonionic surfactant having an HLB value of at most 11 and a cationic surfactant. A homopolymer of at least one monomer constituting the polymer has Tg of at most 50° C.

Abstract: A fluorine-containing urethane compound of the general formula: [Rf-A1-(X1(OH))—(Y1)a—OC(?O)NH—]mI[—NHC(?O)O—Y2]n[—NHC(?O)O—((ClCH2—)X2O)b—R1]k ??(1) wherein I is a group remaining after an isocyanate group is removed from a polyisocyanate compound, Rf is a perfluoroalkyl group having 2 to 21 carbon atoms, A1 is a direct bond or a divalent organic group having 1 to 21 carbon atoms, X1 and X2 are trivalent linear or branched aliphatic group having 2 to 5 carbon atoms, Y1 is a divalent organic group having 0 to 5 carbon atoms and 0 to 2 nitrogen atoms (provided that at least one carbon atom or nitrogen atom is present) and at least one hydrogen atom, Y2 is a monovalent organic group optionally having a hydroxyl group, and R1 is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, can impart high water- and oil-repellency.

Abstract: A fluoropolymer-based water-and-oil repellant composition which comprises a copolymer comprising units derived from (a) an ethylenic monomer having a perfluoroalkyl group, (b) an ethylenic monomer having a group comprising an aromatic ring and a halogen atom or halogenomethyl group bonded thereto, and (c) an ethylenic monomer copolymerizable with these. The composition imparts excellent water and oil repellency through cold cure.

Abstract: A fluorine-containing urethane compound of the general formula: [Rf-A1-(X1(OH))—(Y1)a—OC(?O)NH—]m I [—NHC(?O)O—Y2]n[—NHC(?O)O—((ClCH2—)X2O)b—R1]k ??(1) wherein I is a group remaining after an isocyanate group is removed from a polyisocyanate compound, Rf is a perfluoroalkyl group having 2 to 21 carbon atoms, A1 is a direct bond or a divalent organic group having 1 to 21 carbon atoms, X1 and X2 are trivalent linear or branched aliphatic group having 2 to 5 carbon atoms, Y1 is a divalent organic group having 0 to 5 carbon atoms and 0 to 2 nitrogen atoms (provided that at least one carbon atom or nitrogen atom is present) and at least one hydrogen atom, Y2 is a monovalent organic group optionally having a hydroxyl group, and R1 is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, can impart high water- and oil-repellency.

Abstract: A fluoropolymer-based water-and-oil repellant composition which comprises a copolymer comprising units derived from (a) an ethylenic monomer having a perfluoroalkyl group, (b) an ethylenic monomer having a group comprising an aromatic ring and a halogen atom or halogenomethyl group bonded thereto, and (c) an ethylenic monomer copolymerizable with these. The composition imparts excellent water and oil repellency through cold cure.

Abstract: Excellent water- and oil-repellency performances resulting from low temperature curing are achieved by an aqueous dispersion type fluorine-containing water- and oil-repellent composition containing a polymer of a perfluoroalkyl group-containing ethylenically unsaturated monomer dispersed in an aqueous medium, wherein the composition contains a nonionic surfactant having an HLB value of at most 11 and a cationic surfactant, and a homopolymer of at lest one monomer constituting the polymer has Tg of at most 50° C.