Abstract: In a system in which user equipment is connected to a packet network and a speech recognition application server is also connected to the packet network for performing speech recognition on speech data from the user equipment, a speech recognition system selectively performs feature extraction at a user end before transmitting speech data to be recognized. The feature extraction is performed only for speech which is to be recognized.

Abstract: A method and a system substantially eliminates an erroneous voice recognition of repetitive elements in word spotting. One preferred embodiment according to the current invention eliminates erroneous voice recognition of repetitive elements by selectively prolonging a response time of words containing repetitive elements. In order to substantially eliminate the errors, in another preferred embodiment according to the current invention, words containing repetitive elements are marked by a silent key word.

Abstract: A method of testing a new vocabulary word is performed using any set of enrollment utterances provided by the user or from an available database. The present method preferably does not use separate training and similarity test utterances. This allows any or all available repetitions of a vocabulary word being enrolled to be used for training (204), therefore improving the robustness of the trained models. Likewise, any or all training repetitions can also be utilized for similarity analysis (212), providing additional test samples which should further improve the detection of acoustically similar words. Additionally, the similarity analysis progresses incrementally and does not need to continue if a confusable word is found. Finally, first and second thresholds could be employed (212, 302) to provide greater flexibility for a user training a speech recognition system.

Abstract: A keyword recognition system for speaker dependent, dynamic time warping (DTW) recognition systems uses all of the trained word templates in the system, (keyword and vocabulary), to determine if an utterance is a keyword utterance or not. The utterance is selected as the keyword if a keyword score indicates a significant match to the keyword template and if the keyword score indicates a better match than do the entirety of scores to the vocabulary word templates.

Abstract: Methods and systems consistent with the present invention enroll a candidate phrase uttered by a user in a dictionary having at least one previously enrolled phrase. The system receives utterances of the candidate phrase and determines whether the first utterance is confusingly similar to a previously enrolled phrase and whether they are consistent with each other. The system then enrolls the candidate phrase in the dictionary according to these determinations.

Abstract: A method for matching an input pattern with a number of stored reference patterns using a dynamic programming matching technique is described. The reference patterns of a reference signal which are at the end of a dynamic programming path for a current input pattern are listed in an active list. The dynamic programming paths are propagated by processing the reference patterns on the active list, and a new active list is generated for the succeeding input pattern. The amount of processing required for each pattern on the active list is reduced by using a pointer which identifies the reference pattern which is the earliest in the sequence of patterns of the current reference signal listed on the new active list during the processing of a preceding dynamic programming path. In a second aspect, a speech recognition interface is used as a control system for a telephony system.

Abstract: In the recognition of coherently spoken words, a plurality of hypotheses is usually built up which end in various words during the recognition process and are then to be continued with further words. To keep the number of words yet to be continued as small as possible, especially in the case of a large vocabulary, it is known to carry out a look-ahead in a limited time space. It is suggested according to the invention to use the same phonemes for the look-ahead as for the actual recognition and to add together the differential sums obtained in the look-ahead for the evaluation of the partial hypothesis which has just ended and which is to be continued, and to compare this sum with a threshold value which depends on the extrapolated minimum total evaluation at the end of the time space of the look-ahead. The searching space for hypotheses to be continued can be limited by this in a particularly favorable manner.

Abstract: A system that synchronously segments a speech waveform using pitch period and a center of the pitch waveform. The pitch waveform center is determined by finding a local minimum of a centroid histogram waveform of the low-pass filtered speech waveform for one pitch period. The speech waveform can then be represented by one or more of such pitch waveforms or segments during speech compression, reconstruction or synthesis. The pitch waveform can be modified by frequency enhancement/filtering, waveform stretching/shrinking in speech synthesis or speech disguise. The utterance rate can also be controlled to speed up or slow down the speech.

Abstract: To construct an inexpensive speech recognition system, a speech recogntion system includes an analyzing unit for extracting a sound, sequentially dividing the sound into a plurality of frames, converting each of the frames sequentially to first data, and sequentially storing the first data to an input pattern memory, a distance calculating unit for reading a predetermined number of the first data from the input pattern memory, reading one of second data from a standard pattern memory, calculating first distances between each of the predetermined number of the first data and the one of the second data, and a judging unit for judging a word representing the sound based on the first distances.

Abstract: A method for determining the location of a pattern, when input in isolation, within a representative input signal is provided. The method aligns the input signal with a signal representative of a plurality of connected patterns, one of which is the same as the pattern within the input signal. The method then determines the location from the results of the aligning step. The location determined using this apparatus can be used to determine an isolated reference model by extracting features of the input signal from the location found. This isolated reference model can then be used to generate a continuous reference model for the pattern, by aligning the isolated reference model with the signals representative of a plurality of connected patterns, one of which is the pattern to be modelled.

Abstract: Compensatory values for compensating a reference pattern to match with an utterance environment of an input speech are employed for determining an environmental variation index to be input to a secondary matching controller, which is responsible for magnitudes of the index smaller than a threshold to hold a second matching section inoperative so that a recognition result of a primary matching of a previous compensated reference pattern is output, and for magnitudes of the index larger than the threshold to operate the second matching section to output a recognition result of a second matching based on a current compensated reference pattern to be stored as a subsequent reference pattern.

Abstract: A pattern recognition method of dynamic time warping of two sequences of feature sets onto each other is provided. The method includes the steps of creating a rectangular graph having the two sequences on its two axes, defining a swath of width r, where r is an odd number, centered about a diagonal line connecting the beginning point at the bottom left of the rectangle to the endpoint at the top right of the rectangle and also defining r-1 lines within the swath. The lines defining the swath are parallel to the diagonal line. Each array element k of an r-sized array is associated with a separate array of the r lines within the swath and for each row of the rectangle, the dynamic time warping method recursively generates new path values for each array element k as a function of the previous value of the array element k and of at least one of the current values of the two neighboring array elements k-1 and k+1 of the array element k.

Abstract: A speech recognition system automatically designates a scope of a partial reference pattern. Plural reference patterns, each of which ends in each of composing frames and starts from a preceding frame, are supposed and cumulative distances at every frame are calculated. A partial reference pattern that has a minimal distance value as compared with all other partial reference patterns is taken as a partial input speech recognizing result.

Abstract: A pattern recognition system and method is disclosed. The method includes the steps of a) providing a noisy test feature set of the input signal, a plurality of reference feature sets of reference templates produced in a quiet environment, and a background noise feature set of background noise present in the input signal, b) producing adapted reference templates from the test feature set, the background noise feature set and the reference feature sets and c) determining match scores defining the match between each of the adapted reference templates and the test feature set. The method can also include adapting the scores before accepting a score as the result. The system and method are described for both Hidden Markov Model (HMM) and Dynamic Time Warping (DTW) scoring units. The system performs the steps of the method.

Abstract: In the first step of a sound morphing process, each sound which forms the basis for the morph is converted into one or more quantitative representations, such as spectrograms. After the representations have been obtained, the temporal axes of the two sounds are matched, so that similar components of the two sounds, such as onsets, harmonic regions and inharmonic regions, are aligned with one another. Other characteristics of the sounds, such as pitch, formant frequencies, or the like, are then matched. Once the energy in each of the sounds has been accounted for and matched to that of the other sound, the two sounds are cross-faded, to produce a representation of a new sound. This representation is then inverted, to generate the morphed sound.

Abstract: To determine the degree of correspondence between a first and a second pattern, the first and the second pattern are mapped to n first (V11 to V1n) and m second (V21 to V2m) feature vectors respectively. For points ({1, 1} to {n, m}) in a subarea of a matrix formed by the n first (V11 to V1n) and m second (V21 to V2m) feature vectors, the distance of the respective first (V11 to V1n) and the second (V21 to V2m) feature vectors is computed, and from the mean distance along an optimum path by means of a DP algorithm. Data regarding the gradient of the respective optimum path are determined during the computation for boundary points of the subarea, and the subarea is dynamically reduced for further computations on the basis of these data. The mean distance is used as the degree of correspondence.