System and method of lattice-based search for spoken utterance retrieval
View Patent ↗A system and method are disclosed for retrieving audio segments from a spoken document. The spoken document preferably is one having moderate word error rates such as telephone calls or teleconferences. The method comprises converting speech associated with a spoken document into a lattice representation and indexing the lattice representation of speech. These steps are performed typically off-line. Upon receiving a query from a user, the method further comprises searching the indexed lattice representation of speech and returning retrieved audio segments from the spoken document that match the user query.
1. A method comprising:
converting, via a processor, speech from a spoken document into a lattice representation comprising phones from the speech, wherein the lattice representation belongs to a recognition network represented as weighted finite state machines, and wherein the phones have a pronunciation length longer than a minimum pronunciation length; and
indexing the lattice representation for word and topic searching.
2. The method of claim 1 , wherein the method further comprises converting of the speech and indexing of the lattice representation occur off-line.
3. The method of claim 1 , wherein the converting of speech further comprises causing the processor to provide timing information to the lattice representation.
4. The method of claim 1 , wherein the converting of the speech occurs via automatic speech recognition.
5. The method of claim 4 , wherein the automatic speech recognition is Hidden Markov Model based.
6. The method of claim 5 , wherein the automatic speech recognition is large vocabulary continuous speech recognition.
7. The method of claim 5 , wherein acoustic models used in the automatic speech recognition are decision tree state clustered triphones.
8. The method of claim 7 , wherein language models used in the automatic speech recognition are pruned backoff trigram models.
9. The method of claim 5 , wherein output distributions are mixtures of Gaussians.
10. A system comprising:
a processor; and
a computer-readable storage medium having instructions stored which, when executed by the processor, cause the processor to perform operations comprising:
converting speech from a spoken document into a lattice representation comprising phones from the speech, wherein the lattice representation belongs to a recognition network represented as weighted finite state machines, and wherein the phones have a pronunciation length longer than a minimum pronunciation length; and
indexing the lattice representation for word and topic searching.
11. The system of claim 10 , the computer-readable storage medium having additional instructions stored which result in operations comprising converting of the speech and indexing of the lattice representation occur off-line.
12. The system of claim 10 , wherein the converting of speech further comprises causing the processor to provide timing information to the lattice representation.
13. The system of claim 10 , wherein the converting of the speech occurs via automatic speech recognition.
14. The system of claim 13 , wherein the automatic speech recognition is Hidden Markov Model based.
15. The system of claim 14 , wherein the automatic speech recognition is large vocabulary continuous speech recognition.
16. The system of claim 14 , wherein acoustic models used in the automatic speech recognition are decision tree state clustered triphones.
17. The system of claim 16 , wherein language models used in the automatic speech recognition are pruned backoff trigram models.
18. The system of claim 14 , wherein output distributions are mixtures of Gaussians.
19. A computer-readable storage device having instructions stored which, when executed by a computing device, cause the computing device to perform operations comprising:
converting speech from a spoken document into a lattice representation comprising phones from the speech, wherein the lattice representation belongs to a recognition network represented as weighted finite state machines, and wherein the phones have a pronunciation length longer than a minimum pronunciation length; and
indexing the lattice representation for word and topic searching.
20. The computer-readable storage device of claim 19 , having additional instructions stored which result in operations comprising converting of the speech and indexing of the lattice representation occur off-line.