System and method for measuring confusion among words in an adaptive speech recognition system

• US 20060064177A1
• Filed: 06/09/2005
• Published: 03/23/2006
• Est. Priority Date: 09/17/2004
• Status: Abandoned Application

• Current Assignee: Nokia Corporation
• Original Assignee: Nokia Corporation
• Inventors: Sivadas, Sunil, Lahti, Tommi, Tian, Jilei
• Application Number:
  US11/148,469
• Publication Number:
  US 20060064177A1
• Time in Patent Office: Days
• US Class Current: 700/1
• CPC Class Codes: G10L 15/183 using context dependencies, e.g. language models
• CPC Class Codes: G10L 15/197 Probabilistic grammars, e.g. word n-grams

Abstract

A system and method are proposed for measuring confusability or similarity between given entry pairs, including text string pairs and acoustic model pairs, in systems such as speech recognition and synthesis systems. A string edit distance (Levenshiten distance) can be applied to measure distance between any pair of text strings. It also can be used to calculate a confusion measurement between acoustic model pairs of different words and a model-driven method can be used to calculate a HMM model confusion matrix. This model-based approach can be efficiently calculated with low memory and low computational resources. Thus it can improve the speech recognition performance and models trained from text corpus.

Claims

1. A method of measuring confusion between word sequences in a word sequence recognition system, comprising:

having a new word sequence entered into an electronic device;

creating a new transcription of the new word sequence using a pronunciation-modeling system;

computing a distance between the new transcription and at least one prior transcription of a prior word sequence stored in a database if such a prior transcription exists; and

if the computed distance is less than a predefined threshold, informing a user of a potential confusion between the new word sequence and the prior word sequence.

2. The method of claim 1, further comprising, before the new transcription is created, determining languages to which the new word sequence likely belongs, and wherein a transcription is created for the new word sequence in each of the likely languages.

3. The method of claim 1, further comprising, if no prior transcriptions exist, adding the new transcription to the database.

4. The method of claim 1, further comprising, after the user is informed of the potential confusion, permitting the user to choose an alternative word sequence for at least one of the new word sequence and the prior word sequence.

5. The method of claim 1, wherein the word sequence recognition system is formed by:

selecting an acoustic subword unit set covering languages of interest;

modeling subword units for the language using a statistical modeling technique; and

storing the trained acoustic models for use in later recognition.

6. The method of claim 5, wherein the statistical modeling technique involves the use of hidden Markov models which are trained offline using a large speech corpus, and wherein the large speech corpus is segmented into the subword unit set.

7. The method of claim 1, wherein the distance is computed between the new transcription and at least one prior transcription of a prior word sequence using a string edit distance metric.

8. The method of claim 7, wherein the string edit distance comprises a Levenshtein distance.

9. A computer program product for measuring confusion between word sequences in a word sequence recognition system, comprising:

computer code for having a new word sequence entered into an electronic device;

computer code for creating a new transcription of the new word sequence using a pronunciation-modeling system;

computer code for computing a distance between the new transcription and at least one prior transcription of a prior word sequence stored in a database if such a prior transcription exists; and

computer code for, if the computed distance is less than a predefined threshold, informing a user of a potential confusion between the new word sequence and the prior word sequence.

10. The computer program product of claim 9, further comprising computer code for, before the new transcription is created, determining languages to which the new word sequence likely belongs, and wherein a transcription is created for the new word sequence in each of the likely languages.

11. The computer program product of claim 9, further comprising computer code for, if no prior transcriptions exist, adding the new transcription to the database.

12. The computer program product of claim 9, further comprising computer code for, after the user is informed of the potential confusion, permitting the user to choose an alternative word sequence for at least one of the new word sequence and the prior word sequence.

13. The computer program product of claim 9, wherein the word sequence recognition system is formed by:

selecting an acoustic subword unit set covering languages of interest;

modeling subword units for the language using a statistical modeling technique; and

storing the trained acoustic models for use in later recognition.

14. The computer program product of claim 13, wherein the statistical modeling technique involves the use of hidden Markov models which are trained offline using a large speech corpus, and wherein the large speech corpus is segmented into the subword unit set.

15. The computer program product of claim 9, wherein the distance is computed between the new transcription and at least one prior transcription of a prior word sequence using a string edit distance metric.

16. The computer program product of claim 15, wherein the string edit distance comprises a Levenshtein distance.

17. An electronic device, comprising:

a processor; and

a memory unit communicatively connected to the processor and including a computer program product for measuring confusion between word sequences in a word sequence recognition system, the computer program product including;

computer code for having a new word sequence entered into the electronic device;

computer code for creating a new transcription of the new word sequence using a pronunciation-modeling system;

computer code for computing a distance between the new transcription and at least one prior transcription of a prior word sequence stored in a database if such a prior transcription exists; and

computer code for, if the computed distance is less than a predefined threshold, informing a user of a potential confusion between the new word sequence and the at least one prior word sequence.

18. The electronic device of claim 17, wherein the memory unit further includes computer code for, before the new transcription is created, determining languages to which the new word sequence likely belongs, and wherein a transcription is created for the new word sequence in each of the likely languages.

19. The electronic device of claim 17, wherein the word sequence recognition system is formed by:

selecting an acoustic subword unit set covering languages of interest;

modeling subword units for the language using a statistical modeling technique; and

storing the trained acoustic models for use in later recognition.

20. The electronic device of claim 17, wherein the distance is computed between the new transcription and at least one prior transcription of a prior word sequence using a string edit distance metric.