Methods and Apparatus for Use in Speech Recognition Systems for Identifying Unknown Words and for Adding Previously Unknown Words to Vocabularies and Grammars of Speech Recognition Systems
First Claim
1. A signal-bearing medium tangibly embodying a program of machine-readable instructions executable by a digital processing apparatus of a computer system to perform speech recognition operations, the speech recognition operations comprising:
- detecting at least a target word known to an acoustic vocabulary but unknown to an embedded grammar of a language model of the speech recognition system;
assigning a language model probability to the target word;
calculating a sum of an acoustic and language model confidence score for the target word and words already included in the embedded grammar of the language model; and
if the sum of the acoustic and language model probability for the target word is greater than the sum of the acoustic and language model probability for the words already included in the embedded grammar, adding the target word to the language model.
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Abstract
The present invention concerns methods and apparatus for identifying and assigning meaning to words not recognized by a vocabulary or grammar of a speech recognition system. In an embodiment of the invention, the word may be in an acoustic vocabulary of the speech recognition system, but may be unrecognized by an embedded grammar of a language model of the speech recognition system. In another embodiment of the invention, the word may not be recognized by any vocabulary associated with the speech recognition system. In embodiments of the invention, at least one hypothesis is generated for an utterance not recognized by the speech recognition system. If the at least one hypothesis meets at least one predetermined criterion, a sword or more corresponding to the at least one hypothesis is added to the vocabulary of the speech recognition system. In other embodiments of the invention, before adding the word to the vocabulary of the speech recognition system, the at least one hypothesis may be presented to the user of the speech recognition system to determine if that is what the used intended when the user spoke.
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21 Claims
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1. A signal-bearing medium tangibly embodying a program of machine-readable instructions executable by a digital processing apparatus of a computer system to perform speech recognition operations, the speech recognition operations comprising:
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detecting at least a target word known to an acoustic vocabulary but unknown to an embedded grammar of a language model of the speech recognition system; assigning a language model probability to the target word; calculating a sum of an acoustic and language model confidence score for the target word and words already included in the embedded grammar of the language model; and if the sum of the acoustic and language model probability for the target word is greater than the sum of the acoustic and language model probability for the words already included in the embedded grammar, adding the target word to the language model. - View Dependent Claims (2, 3, 4)
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5. A signal-bearing medium tangibly embodying a program of machine-readable instructions executable by a digital processing apparatus of a computer system to perform speech recognition operations, the speech recognition operations comprising:
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detecting an utterance having a low acoustic score within an acoustic vocabulary of the speech recognition system indicating that the utterance may correspond to an out-of-vocabulary word; generating at least one new word hypothesis comprised of at least one of a phone- or syllable sequence using confidence scores derived from probabilities contained in a database of viable phone and syllable sequences; and if the at least one new word hypothesis meets a pre-determined criterion, adding a word corresponding to the at least one new word hypothesis to the vocabulary of the speech recognition system. - View Dependent Claims (6, 7, 8)
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9. A signal-bearing medium tangibly embodying a program of machine-readable instructions executable by a digital processing apparatus of a computer system to perform speech recognition operations in a speech recognition system, the speech recognition operations comprising:
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detecting an utterance not recognized by at least a first one of an acoustic vocabulary, embedded grammar, and viable phone/syllable sequence library of the speech recognition system; generating at least one hypothesis for the utterance, wherein the hypothesis is based on information derived from a second one of an acoustic vocabulary, embedded grammar and viable phone/syllable sequence library of the speech recognition system; calculating a confidence score for the at least one hypothesis and for members of the first one of the acoustic vocabulary, embedded grammar and viable phone/syllable sequence library of the speech recognition system; comparing the confidence scores calculated for the at least one hypothesis and for members of the first one of the acoustic vocabulary, embedded grammar and viable phone/syllable sequence library of the speech recognition system; and adding information to the first one of an acoustic vocabulary, embedded grammar and viable phone/syllable sequence corresponding to the hypothesis if a pre-determined criterion based on the comparison is met. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16)
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17. A speech recognition system comprising:
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a speech input for receiving speech from a user of the speech recognition system; an open set comprised of at least one open vocabulary and at least one open embedded grammar associated with a language model implemented in the speech recognition system; a hierarchical mapping system for identifying utterances not recognized by at least one of the open vocabulary and open embedded grammar of the speech recognition system;
for generating hypotheses for the unrecognized utterances using confidence scores based at least in part on one of viable phone/syllable sequence information, acoustic vocabulary information and grammar information; and
for adding information corresponding to the hypotheses to at least one of the open vocabulary and embedded grammar of the speech recognition system if a pre-determined criterion is met; anda confidence score system for generating confidence scores for use by the hierarchical mapping system. - View Dependent Claims (18, 19, 20, 21)
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Specification