Pattern matching for large vocabulary speech recognition systems

An architectural arrangement for a speech recognition system having a plurality of acoustic models residing in a data store, comprising:

• an acoustic front-end node receptive of continuous speech input, the acoustic front-end node operable to generate a sequence of acoustic feature vectors that represent temporal and spectral behavior of the speech input;
• a first pattern matching node having a first data processor and a first memory space accessible to the first data processor, the first pattern matching node adapted to receive a first group of acoustic feature vectors from the sequence of acoustic feature vectors into the first memory space, the first pattern matching node further operable to load a first acoustic model in the first memory space from the data store and to determine a similarity measure for each acoustic feature vector of the first group of acoustic feature vectors in relation to the first acoustic model using the first data processor;
• and
• a second pattern matching node having a second data processor and a second memory space accessible to the second data processor, the second pattern matching node adapted to receive the first group of acoustic feature vectors into the second memory space, the second pattern matching node further operable to load a second acoustic model in the second memory space from the data store and to determine a similarity measure for each acoustic feature vector of the first group of acoustic feature vectors in relation to the second acoustic model using the second data processor.

A method for improving pattern matching in a speech recognition system having a plurality of acoustic models, comprising:

• receiving continuous speech input;
• generating a sequence of acoustic feature vectors that represent temporal and spectral behavior of the speech input;
• retrieving a first group of acoustic feature vectors from the sequence of acoustic feature vectors into a first memory workspace accessible to a first processor;
• retrieving a first acoustic model from the plurality of acoustic models into the first memory workspace;
• retrieving a first group of acoustic feature vectors from the sequence of acoustic feature vectors into a second memory workspace accessible to a second processor;
• retrieving a second acoustic model from the plurality of acoustic models into the second memory workspace;
• and
• determining a similarity measure for each acoustic feature vector of the first group of acoustic feature vectors in relation to the first acoustic model by the first processor contemporaneously with determining a similarity measure for each acoustic feature vector of the first group of acoustic feature vectors in relation to the second acoustic model by the second processor.

A method for improving the decoding process in a speech recognition system, comprising:

• generating a search space that is comprised of observed acoustic data, the search space having an active search space;
• partitioning the active search space amongst a plurality of processing nodes;
• and
• performing a searching operation on the active search space allocated to each processing node, such that searching operations occur concurrently on at least two of the plurality of processing nodes.

A distributed architectural arrangement for a speech recognition system, the speech recognition system operable to generate a search space defined by a plurality of lexical trees, comprising:

• a first searching node having a first data processor and a first memory space accessible to the first data processor, the first searching node adapted to receive similarity measures that correlate speech input to a plurality of acoustic models and operable to evaluate a first lexical tree based on the similarity measures;
• a second searching node having a second data processor and a second memory space accessible to the second data processor, the second searching node adapted to receive the similarity measures and operable to evaluate a second lexical tree based on the similarity measures;
• and
• a communication link interconnecting the first and second searching nodes.