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5761639 Method and apparatus for time series signal recognition with signal variation proof learning  
A time series signal recognition capable of obtaining a high recognition rate even for the speech data with low S/N ratio in noisy environments. The time series signals are recognized by extracting...
5758022 Method and apparatus for improved speech recognition from stress-induced pronunciation variations with a neural network utilizing non-linear imaging characteristics  
Speech recognition of Lombard-induced speech at a high rate of recognition is shown using a neural network (NN) utilizing nonlinear imaging characteristics. In a training phase, systematic...
5757937 Acoustic noise suppressor  
In an acoustic noise suppressor, a power spectrum component and a phase component are extracted from an input signal by a frequency analysis part, while at the same time a check is made in a...
5752226 Method and apparatus for reducing noise in speech signal  
A method and apparatus for reducing noise in an input speech signal, in which the apparatus includes a noise reducing unit that has a variable noise reducing amount based on a control signal that...
5749068 Speech recognition apparatus and method in noisy circumstances  
An estimated-SN(Signal Noise)-ratio is calculated for a time-series feature vector of noise-superimposed speech by using a noise-free speech model and a noise model. A noise-superimposed model is...
5742927 Noise reduction apparatus using spectral subtraction or scaling and signal attenuation between formant regions  
A noise reduction apparatus and method for enhancing noisy speech signal which applies to the spectral component signals of a time-varying input signal either a spectral substraction process or a...
5742928 Apparatus and method for speech recognition in the presence of unnatural speech effects  
A speech recognition apparatus recognizes utterances of unnatural speech having a higher performance of recognition accuracy with a smaller amount of speech learning data. The speech recognition...
5732392 Method for speech detection in a high-noise environment  
In method for detecting a speech period in a high-noise environment, the variation in the spectrum of an input signal per unit time is calculated over an analysis frame period, and when the...
5732390 Speech signal transmitting and receiving apparatus with noise sensitive volume control  
A speech signal transmitting receiving apparatus, such as a portable telephone set, includes a speech signal transmitting encoding circuit, a noise domain detection unit, a noise level detection...
5732190 Number-of recognition candidates determining system in speech recognizing device  
A number-of-recognition candidates determining system in a speech recognition device comprises an SN ratio calculator for calculating an SN ratio of an inputted speech to the environmental noise,...
5732141 Detecting voice activity  
Method and apparatus for detecting voice activity in an audio signal, the method comprising computing the autocorrelation coefficients of the signal, identifying a first autocorrelation vector...
5727072 Use of noise segmentation for noise cancellation  
What is disclosed is a method and system for improving noise cancellation in a signal containing speech by classifying noise frames by their characteristics, and estimating noise based on only one...
5727124 Method of and apparatus for signal recognition that compensates for mismatching  
Disclosed is a method for drastically reducing the average error rate for signals under mismatched conditions. The method takes a signal (e.g., speech signal) and a set of stored representations...
5727121 Sound processing apparatus capable of correct and efficient extraction of significant section data  
Input sound information is converted to digital sound data, and characteristic parameter values are extracted from the digital sound data. Based on the characteristic parameter values, a judging...
5721808 Method for the composition of noise-resistant hidden markov models for speech recognition and speech recognizer using the same  
Noise-resistant speech HMMs are composed by: recording noise in the environment of utterance (S 1 ); preparing HMMs of the noise (S 2 ); transforming the output probability distribution of each of...
5706394 Telecommunications speech signal improvement by reduction of residual noise  
A telecommunications network service overcomes the annoying effects of transmitted noise by signal processing which filters out the noise using a model-based iterative signal estimator. The...
5706393 Audio signal transmission apparatus that removes input delayed using time time axis compression  
An audio signal transmission apparatus for use in a system for judging whether voice or sound is present or not to transmit only the voice presence portion of a digital audio signal which apparatus...
5692017 Receiving circuit  
A receiving circuit has an automatic level setting function for a background noise on the receiver side to generate a background noise free from incongruous aural sensation. This circuit is...
5692103 Method of speech recognition with learning  
In the recognition phase, the signal originating from a sensor is processed to obtain parameters which are compared with those stored in a dictionary in the learning phases so as to recognize the...
5689615 Usage of voice activity detection for efficient coding of speech  
A method for efficient coding of non-active voice periods is disclosed for a speech communication system with (a) a speech encoder, (b) a communication channel and (c) a speech decoder. The method...
5687283 Pause compressing speech coding/decoding apparatus  
A pause compressing speech coding/decoding apparatus according to the invention can improve the sound quality of decoded speech in terms of sense of hearing, in which the transmission side includes...
5687285 Noise reducing method, noise reducing apparatus and telephone set  
A noise reducing method and device for reducing the noise contained in an input speech signal collects the speech signal with a microphone 11 and converts the speech signal into a digital input...
5684924 User adaptable speech recognition system  
A speech recognition system is disclosed which comprises a core speech recognition program and a plurality of utility program modules for adjusting various recognition parameters such as gain,...
5657422 Voice activity detection driven noise remediator  
A method and apparatus for improving sound quality in a digital cellular radio system receiver. A voice activity detector uses an energy estimate to detect the presence of speech in a received...
5655057 Speech recognition apparatus  
A speech recognition apparatus includes an average vector calculating portion 5, a compensating portion 6, and a matching portion 8. The average vector calculating portion 5 calculates an average...
5649055 Voice activity detector for speech signals in variable background noise  
A voice activity detector (VAD) which determines whether received voice signal samples contain speech by deriving parameters measuring short term time domain characteristics of the input signal,...
5646991 Noise replacement system and method in an echo canceller  
A noise replacement system and method for providing a synthesized noise replacement signal to an output speech channel in an echo cancellation system. A far-end speech signal transmitted through a...
5642465 Linear prediction speech coding method using spectral energy for quantization mode selection  
A speech signal digitized as successive frames is subjected to analysis-by-synthesis in order to obtain, for each frame, quantization values of synthesis parameters allowing reconstruction of an...
5633982 Removal of swirl artifacts from celp-based speech coders  
The perception of speech processed by a CELP based coder, such as a VSELP coder, when operating in noisy background conditions is improved by removing swirl artifacts during silence periods. This...
5623539 Using voice signal analysis to identify authorized users of a telephone system  
A user transparent telephone fraud detection and prevention system employs speech analysis techniques to determine whether at least one participant in a telephone conversation is an authorized user...
5621850 Speech signal processing apparatus for cutting out a speech signal from a noisy speech signal  
A band division process including a Fourier transformation is performed for an inputted speech signal, thereby outputting spectrum signals of plural channels. A cepstrum analysis process is...
5621854 Method and apparatus for objective speech quality measurements of telecommunication equipment  
A telecommunications testing apparatus comprising a signal generator which generates a speech-like synthetic signal, which is supplied to the input of a telecommunication apparatus to be tested....
5617508 Speech detection device for the detection of speech end points based on variance of frequency band limited energy  
The device detects the beginning and ending portions of speech contained within an input signal based on the variance of frequency band limited energy within the signal. The use of the variance...
5615299 Speech recognition using dynamic features  
A speech recognition technique utilizes a set of N different principal discriminant matrices. Each principal discriminant matrix is associated with a distinct class. The class is an indication of...
5615297 Transmission system for coded speech signals and/or voiceband data  
A digital coder receives either speech or audio-band data. When receiving speech this is coded by a digital speech coder and formatted into frames with parity bits. If modulated data are present...
5611019 Method and an apparatus for speech detection for determining whether an input signal is speech or nonspeech  
The speech detection apparatus comprises: a reference model maker for extracting a plurality of parameters for a speech detection from training data, and for making a reference model based on the...
5598506 Apparatus and a method for concealing transmission errors in a speech decoder  
A receiver in a frame based radio communication system includes a speech decoder of the source-filter type which is controlled by internal state variable updated on a frame by frame basis for...
5596678 Lost frame concealment  
A receiver in a frame based radio communication system includes a speech decoder of the source-filter type which is controlled by internal state variables updated on a frame by frame basis for...
5590242 Signal bias removal for robust telephone speech recognition  
A signal bias removal (SBR) method based on the maximum likelihood estimation of the bias for minimizing undesirable effects in speech recognition systems is described. The technique is readily...
5583968 Noise reduction for speech recognition  
A neural network for noise reduction for speech recognition in a noisy environment uses an algorithm for automatic network generation which automatically selects a suitable signal representation....
5579435 Discriminating between stationary and non-stationary signals  
Signal frames containing background sounds in a mobile radio communication system are tested for stationarity. Consecutive measures ΔE n representing spectral changes in said signals from frame...
5577161 Noise reduction method and filter for implementing the method particularly useful in telephone communications systems  
Noise reduction using a digital signal processor includes receiving an input signal which may include a noise-corrupted information signal and/or a noise signal, filtering the noise-corrupted...
5577163 System for recognizing or counting spoken itemized expressions  
A speech categorization system includes first and second timers which generate first and second measured durations indicative of duration of selected higher and lower amplitude segments included in...
5574824 Analysis/synthesis-based microphone array speech enhancer with variable signal distortion  
A microphone array speech enhancement algorithm based on analysis/synthesis filtering that allows for variable signal distortion. The algorithm is used to suppress additive noise and interference....
5572622 Rejected frame concealment  
A method and apparatus for improving the decoding of audio signals is disclosed. In a receiver of a frame based radio communication system, rejected frames are concealed according to a first...
5572623 Method of speech detection  
A method for detecting the start and end of speech from a noisy signal including the steps of: detecting a voiced frame; searching for noise frames preceding this voiced frame; ...
5561737 Voice actuated switching system  
A voice-actuated switching system connects one or more microphones to an audio line in accordance with the output signal levels from each of the microphones. To reduce the effects of degradation of...
5553134 Background noise compensation in a telephone set  
An automated method for modifying a speech signal communicated over a telephone network by applying a gain factor in a telephone set before any side tone is added thereto. The gain factor is a...
5548681 Speech dialogue system for realizing improved communication between user and system  
In the system, a speech input uttered by a human is received by a microphone which outputs microphone output signals. The speech input received by the microphone is then recognized by a speech...
5539859 Method of using a dominant angle of incidence to reduce acoustic noise in a speech signal  
Fourier transform processing is applied to digital signals obtained by analog-to-digital conversion of signals supplied by two microphones spaced by a fixed distance to produce two series of...