Large vocabulary connected speech recognition system and method of language representation using evolutional grammar to represent context free grammars
First Claim
1. A method for use in a grammar-based recognition system having a grammar represented by a grammar network comprised of arcs interconnecting nodes, ones of the arcs being terminal arcs representative of respective recognition models and others of the arcs being non-terminal arcs representing respective grammar sub-networks, each of the arcs having a source node and a destination node, and in which feature scores are input to the grammar network and resulting cumulative hypothesis scores are propagated through the models to produce cumulative hypothesis scores at various ones of the nodes, the method comprising the steps ofdefining a first transition network having at least one non-terminal arc,in response to the appearance of a hypothesis score meeting a predetermined turn-on criterion at the source node of a non-terminal arc, recursively replacing that non-terminal arc with transition networks until all of the arcs emanating from said source node are terminal arcs, andinstantiating the recognition models represented by all of the arcs emanating from said source node.
6 Assignments
0 Petitions
Accused Products
Abstract
A method of recognizing speech input selectively creates and maintains grammar representations of the speech input in essentially real time. Speech input frames received by a speech recognition system. Grammar representations are created for each speech frame and a probability score is derived for the representations indicating the probability of the accuracy of the representations to the speech input. Representations having a probability score below a predetermined threshold are not maintained. Those grammar representations having probability scores above predetermined threshold are maintained. As more speech frames are received by the system, additional grammar representations are created and the probability scores are updated. When the entire speech input has been received, the chain of grammar representations having the highest probability score is identified as the speech input.
71 Citations
4 Claims
-
1. A method for use in a grammar-based recognition system having a grammar represented by a grammar network comprised of arcs interconnecting nodes, ones of the arcs being terminal arcs representative of respective recognition models and others of the arcs being non-terminal arcs representing respective grammar sub-networks, each of the arcs having a source node and a destination node, and in which feature scores are input to the grammar network and resulting cumulative hypothesis scores are propagated through the models to produce cumulative hypothesis scores at various ones of the nodes, the method comprising the steps of
defining a first transition network having at least one non-terminal arc, in response to the appearance of a hypothesis score meeting a predetermined turn-on criterion at the source node of a non-terminal arc, recursively replacing that non-terminal arc with transition networks until all of the arcs emanating from said source node are terminal arcs, and instantiating the recognition models represented by all of the arcs emanating from said source node.
Specification