Threshold Technology, Inc.

Thomas B Martin

Marvin B Herscher

Robert B Cox

An apparatus which receives spoken input training words and a subsequent spoken input command word and generates a correlation function is indicative of the resemblance of the command word to each training word. A feature extraction means processes received input words and generates digital feature output signals on particular ones of a number of feature output lines. Means are provided for storing, as a time dependent matrix, the status of the feature signals which occur during each training word. Means are also provided for storing as a time dependent matrix, the status of the feature signals which occur during the command word. Further means are provided for comparing, member by member, the command word matrix with each training word matrix and for generating a correlation figure which reflects each comparison. In a preferred embodiment of the invention, means are provided for time normalizing the matrices representative of the training words and the command word before the comparisons are made.

Word recognition apparatus and method

The present invention pertains to an apparatus which receives acoustic input, the input including words spoken in isolation, finds the word boundary instants at which a word begins and ends, and performs recognition functions on the words. A feature of the invention is the compensation for breath noise after the true end of a word, using a variable backup of the estimated word end. The apparatus includes means for generating feature signals indicative of feature characteristics in the received input and further includes means for comparing the feature signals which occurred during determined time boundaries with stored features corresponding to words in a vocabulary. The invention is directed to an improved system for detecting word boundaries which includes a means responsive to the input for generating a first feature signal indicative of the substantially continuing presence of speech-like sounds which meet a first selection criterion. Means are provided for storing the feature signals which occur during the presence of this first feature signal. Further means, responsive to the input, are provided for generating a second feature signal indicative of the presence of speech-like sounds which meet a second selection criterion, this second selection criterion being more restrictive than the first selection criterion. Means are also provided for determining the last occurrence of the second feature signal among the stored feature signals. The end boundary of an input spoken word is determined as a function of this last occurrence.

Word boundary detector for speech recognition equipment

An apparatus and method for recognizing the occurrence of a command word from among input speech that may be continuous in form. In accordance with the invention, means are provided for generating feature signals which depend on the features of an input word being spoken. The feature signals are processed to determine the time interval of occurrence of a predetermined sequence of features. Also provided is a means for comparing the feature signals which occur during the determined time interval with a stored set of features that are expected to occur characteristically during the command word to determine the degree of correlation therebetween.

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Delran, NJ, United States of America

Thomas B Martin