Methods and apparatus for verifying the originator of a sequence of operations
First Claim
1. A method of verifying that a sequence of operations originates from a specific entity, comprising the steps ofextracting a test sequence of sets of features of the results of the operations, one set corresponding to each operation,matching the said test sequence of sets of features against a first stored finite state machine model derived from sets of features of the results of the same sequence of operations when originated by a plurality of entities,matching the said test sequence of features against a second stored finite state machine model derived from sets of features of the results of the same sequence of operations when originated by the specific entity, andcomparing the results of the matching steps to indicate whether the test sequence of operations originated from the specific entity.
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Abstract
Speaker verification is important in such applications as financial transactions which are to be carried out automatically by telephone. False acceptances of a speaker cause serious problems but so do frequent false rejections in view of the annoyance caused. Some of the problems of speaker verification are reduced in the invention by forming Hidden Markov Models (HMMs) for each of a number of words using features of utterances of these words from a large number of speakers. These models are known as world models. In addition, for every person whose speech is to be recognized, one HMM is formed for each of the words as uttered by that person. These models are known as personal models. In verification, a person is prompted to repeat a string of isolated or connected words (15) and features from each of these words are extracted (16). Next, the probabilities that these features could have been generated by the world models for these words and by the personal model of that person are calculated, respectively (17 and 18) and these probabilities are compared (19) for each word. A decision (23) on verification is based on a poll (22) of these comparisons.
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Citations
40 Claims
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1. A method of verifying that a sequence of operations originates from a specific entity, comprising the steps of
extracting a test sequence of sets of features of the results of the operations, one set corresponding to each operation, matching the said test sequence of sets of features against a first stored finite state machine model derived from sets of features of the results of the same sequence of operations when originated by a plurality of entities, matching the said test sequence of features against a second stored finite state machine model derived from sets of features of the results of the same sequence of operations when originated by the specific entity, and comparing the results of the matching steps to indicate whether the test sequence of operations originated from the specific entity.
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26. Apparatus for verifying that a sequence of operations originated from a specific entity, comprising
means for storing data specifying first and second finite state machines, the data for the first machine having been derived from sets of features of the results of a sequence of operations originated by a plurality of entities, the data for the second machine having been derived from sets of features of the results of the same sequence of operations originated by a specific entity, means for extracting a test sequence of sets of features from the results of a sequence of operations which are alleged to have been originated by the said specific entity, means for matching the said test sequence against the first and second said machines, respectively, and means for comparing results from the matching means to indicate whether the test sequence was originated by the said specific entity.
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36. A method of verifying that operations originate from a specific entity, comprising the steps of
extracting test results of the operations, matching the said test results against a first model derived from results of the same operations when originated by a plurality of entities, matching the said test results against a second model derived from results of the same operations when originated by the specific entity, and comparing the results of the matching steps to indicate whether the test results originated from the specific entity.
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37. A method of identifying an utterance, which comprises:
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extracting a test sequence of sets of features for said utterance; matching said test sequence of sets of features against a first stored finite state machine model derived from sets of features corresponding to a group of utterances; matching said test sequence of sets of features against a second stored finite state machine model derived from sets of features corresponding to said given utterance; and comparing the results of the matching steps to indicate whether said utterance corresponds to said given utterance. - View Dependent Claims (38, 39)
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40. Apparatus for identifying an utterance, comprising
means for storing data specifying first and second finite state machines, the data for the first machine having been derived from sets of features corresponding to a group of utterances, and the data for the second machine having been derived from sets of features corresponding to said given utterance; -
means for extracting a test sequence of sets of features for said utterance; means for matching said test sequence against the first and second finite state machines, respectively; means for comparing results from said matching means to indicate whether said utterance corresponds to said given utterance.
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Specification