Automatic segmentation in speech synthesis

1. A method for automatic segmentation of speech to generate a speech inventory, the method comprising:

initializing, via a processor, a Hidden Markov Model (HMM) using seed input data;

performing a segmentation of the HMM into speech units to generate phone labels;

correcting, via the processor, the segmentation of the speech units by performing the steps:

re-estimating the HMM based on a current version of the phone labels;

embedded re-estimating of the HMM; and

updating the current version of the phone labels using spectral boundary correction.

2. The method of claim 1 , further comprising concatenating the speech units to synthesize speech.

3. The method of claim 2 , further comprising iteratively performing the re-estimating, embedded re-estimating, and updating steps until no perceptual improvement of synthesis quality is detected between iterations.

4. The method of claim 1 , wherein the seed input data is selected from the group consisting of hand-labeled bootstrapped data, speaker-independent HMM bootstrapped data, and flat start data.

5. The method of claim 1 , further comprising adjusting boundaries of the phone labels within specified time windows.

6. The method of claim 1 , further comprising identifying context-dependent time windows around speech unit boundaries, wherein the speech unit boundaries include one or more of:

a vowel-to-vowel boundary;

a vowel-to-nasal boundary;

a vowel-to-voiced stop boundary;

a vowel-to-liquid boundary;

a vowel-to-unvoiced stop boundary;

a vowel-to-voiced fricative boundary;

an unvoiced stop-to-vowel boundary;

a nasal-to-vowel boundary;

a voiced stop-to-vowel boundary

a liquid-to-vowel boundary;

an unvoiced fricative-to-vowel boundary; and

a voiced fricative-to-vowel boundary.

7. The method of claim 6 , wherein the context-dependent time windows are empirically determined by adjacent phones.

8. A computer-readable storage medium storing a set of program instructions executable on a processor device and usable to reduce speech unit boundaries, the instructions causing the processing device to perform the steps:

aligning a trained set of HMMs to produce phone labels that are segmented, wherein each phone label has a spectral boundary;

performing a spectral boundary correction on the phone labels, wherein spectral boundary correction re-aligns each spectral boundary using bending points of spectral transitions; and

synthesizing speech using the phone labels having spectral boundary correction.

9. The computer-readable storage medium of claim 8 , wherein the instructions further comprise bootstrapping the set of HMMs with at least one of speaker-dependent HMMs and speaker-independent HMMs.

10. The computer-readable storage medium of claim 8 , wherein the instructions further comprise:

initializing the set of HMMs;

re-estimating the set of HMMs; and

performing embedded re-estimation on the set of HMMs.

11. The computer-readable storage medium of claim 10 , wherein the instructions further comprise iteratively performing a first alignment on a trained set of HMMs to produce phone labels that are segmented and performing spectral boundary correction on the phone labels.

12. The computer-readable storage medium of claim 11 , wherein the instructions further comprise training the set of HMMs using phone labels having boundaries that have been re-aligned using spectral boundary correction.

13. The computer-readable storage medium of claim 8 , wherein the instruction further comprise performing a Viterbi alignment on the trained set of HMMs to produce phone labels that are segmented.

14. The computer-readable storage medium of claim 8 , wherein the instructions further comprise performing spectral boundary correction on the phone labels within a context-dependent time window.

15. The computer-readable storage medium of claim 14 , wherein the instructions further comprise determining empirically the context-dependent time window using adjacent phones.

16. The computer-readable storage medium of claim 8 , wherein each spectral boundary is between a first phone class and a second phone class.

17. A system for automatic segmentation of speech to generate a speech inventory, the system comprising:

a processor;

a first module configured to control the processor to initialize a Hidden Markov Model (HMM) using seed input data;

a second module configured to control the processor to perform a segmentation of the HMM into speech units to generate phone labels;

a third module configured to control the processor to correct the segmentation of the speech units by performing the steps:

re-estimating the HMM based on a current version of the phone labels;

embedded re-estimating of the HMM; and

updating the current version of the phone labels using spectral boundary correction.

18. The system of claim 17 , further comprising a module configured to control the processor to concatenate the speech units to synthesize speech.

19. The system of claim 18 , further comprising a module configured to control the processor to iteratively perform the re-estimating, embedded re-estimating, and updating steps until no perceptual improvement of synthesis quality is detected between iterations.

20. The system of claim 17 , wherein the seed input data is selected from the group consisting of hand-labeled bootstrapped data, speaker-independent HMM bootstrapped data, and flat start data.