Method of dynamically altering grammars in a memory efficient speech recognition system
First Claim
1. A method for allocating memory in a speech recognition system comprising the steps of:
- acquiring a first set of data structures that contain a grammar, a word subgrammar, a phone subgrammar and a state subgrammar, each of the subgrammars related to the grammar;
acquiring a speech signal;
performing a probabilistic search using the speech signal as an input, and using the grammar and the subgrammars as possible inputs; and
allocating memory for one of the subgrammars when a transition to that subgrammar is made during the probabilistic search.
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Abstract
A method of speech recognition that uses hierarchical data structures that include a top level grammar and various related subgrammars, such as word, phone, and state subgrammars. A speech signal is acquired, and a probabilistic search is performed using the speech signal as an input, and using the (unexpanded) grammars and subgrammars as possible inputs. Memory is allocated to a subgrammar when a transition to that subgrammar is made during the probabilistic search. The subgrammar may then be expanded and evaluated, and the probability of a match between the speech signal and an element of the subgrammar for which memory has been allocated may be computed. Because unexpanded grammars and subgrammars take up very little memory, this method enables systems to recognize and process a larger vocabulary that would otherwise be possible. This method also permits grammars and subgrammars to be added, deleted, or selected by a remote computer while the speech recognition system is operating, allowing speech recognition systems to have a nearly unlimited vocabulary.
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Citations
36 Claims
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1. A method for allocating memory in a speech recognition system comprising the steps of:
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acquiring a first set of data structures that contain a grammar, a word subgrammar, a phone subgrammar and a state subgrammar, each of the subgrammars related to the grammar;
acquiring a speech signal;
performing a probabilistic search using the speech signal as an input, and using the grammar and the subgrammars as possible inputs; and
allocating memory for one of the subgrammars when a transition to that subgrammar is made during the probabilistic search. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. In a speech recognition system, a method for recognizing speech comprising the steps of:
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acquiring a first set of data structures that contain a grammar, a word subgrammar, a phone subgrammar and a state subgrammar, each of the subgrammars related to the grammar;
acquiring a speech signal;
performing a probabilistic search using the speech signal as an input, and using the grammar and the subgrammars as possible inputs;
allocating memory for one of the subgrammars when a transition to that subgrammar is made during the probabilistic search; and
computing a probability of a match between the speech signal and an element of the subgrammar for which memory has been allocated. - View Dependent Claims (12, 13, 14, 15, 16, 17, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33)
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18. In a speech recognition system, a method for recognizing speech comprising the steps of:
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acquiring a first set of data structures that contain a top level grammar and a plurality subgrammars, each of the subgrammars hierarchically related to the grammar and to each other;
acquiring a speech signal;
performing a probabilistic search using the speech signal as an input, and using the top level grammar and the subgrammars as possible inputs;
allocating memory for specific subgrammars when transitions to those specific subgrammars are made during the probabilistic search; and
computing probabilities of matches between the speech signal and elements of the subgrammars for which memory has been allocated.
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34. A method for allocating memory in a speech recognition system comprising the steps of:
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acquiring a set of data structures that contain a grammar and one or more subgrammars related to the grammar;
acquiring a speech signal;
performing a probabilistic search using the speech signal as an input, and using the grammar and the subgrammars as possible inputs; and
allocating memory for a selected one or more of the subgrammars when a transition to the selected subgrammar is made during the probabilistic search.
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35. In a speech recognition system, a method for recognizing speech comprising the steps of:
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(a) acquiring a set of data structures that contain a grammar and one or more subgrammars related to the grammar;
(b) receiving spoken input;
(c) using one or more of the data structures to recognize the spoken input;
(d) while the speech recognition system is operating, acquiring a second set of data structures that contain a second grammar and one or more subgrammars related to the second grammar; and
(e) repeating steps (b) and (c), using the second set of data structures in step (c).
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36. In a speech recognition system, a method for recognizing speech comprising the steps of:
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(a) acquiring from a first remote computer a set of data structures that contain a grammar and one or more subgrammars related to the grammar;
(b) receiving spoken input;
(c) using one or more of the data structures to recognize the spoken input;
(d) while the speech recognition system is operating, acquiring a second set of data structures from the first remote computer or from a second remote computer, the second set of data structures containing a second grammar and one or more subgrammars related to the second grammar; and
(e) repeating steps (b) and (c), using the second set of data structures in step (c).
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Specification