Method of pitch mark determination for a speech

• US 20030125934A1
• Filed: 06/03/2002
• Published: 07/03/2003
• Est. Priority Date: 12/14/2001
• Status: Active Grant

• Current Assignee: Industrial Technology Research Institute
• Original Assignee: Industrial Technology Research Institute
• Inventors: Kao, Yung-An, Chen, Jau-Hung
• Granted Patent: US 7,043,424 B2
• Time in Patent Office: Days
• US Class Current: 704/207
• CPC Class Codes: G10L 25/90 Pitch determination of speech signals

Abstract

A method of pitch mark determination for a speech, includes: acquiring a fundamental frequency point and fundamental frequency passband signals by using an adaptable filter; detecting a number of passing zero positions of the fundamental frequency passband signals; and generating at least a set of pitch marks from a number of passing zero positions. Lastly, estimating several sets of pitch marks generates the best set of pitch marks.

Claims

1. A method of pitch mark determination for a speech, the method comprising the steps of:

acquiring a fundamental frequency point and a fundamental frequency passband signal by using an adaptable filter;

detecting a plurality of passing zero positions of the fundamental frequency passband signal; and

generating at least a set of pitch marks from a plurality of passing zero positions.

2. The method according to claim 1, wherein the fundamental frequency point is a position with maximum energy found in a corresponding fundamental frequency range of a spectrum at different sampling frequencies.

3. The method according to claim 2, wherein the position with maximum energy is found by calculating the average spectrum energy of the zero position to the position with maximum energy.

4. The method according to claim 3, wherein the position with maximum energy is multiple the fundamental frequency of the fundamental frequency point.

5. The method according to claim 1, wherein the step of acquiring a fundamental frequency point and a fundamental frequency passband signal by using an adaptable filter further comprising the following steps:

capturing a plurality of speech signals of the speech and generating a first function;

finding a fundamental frequency point by performing a transform function on the first function;

retaining a plurality of spectrum points near the fundamental frequency point and generating a second function; and

finding a fundamental passband frequency signals by performing an inverse transform function on the second function.

6. The method according to claim 5, wherein the spectrum points near the fundamental frequency point lie between the region [3, the fundamental frequency point+2] and the region [N-(the fundamental frequency point+2), N−

3], which corresponds to the first function after transformation, while the number of the speech signals is N.

7. The method according to claim 6, wherein the fundamental frequency passband signals are the real part of the speech signals in the region [N/4, 3N/4] except the N/2 speech signals.

8. The method according to claim 1, wherein the step of generating at least a set of pitch marks comprises generating the pitch marks by finding a highest position of the speech signals from the passing zero positions.

9. The method according to claim 1, wherein the step of generating at least a set of pitch marks comprises generating the pitch marks by finding a second high position of the speech signals from the passing zero positions.

10. The method according to claim 1, wherein the step of generating at least a set of pitch marks comprises generating the pitch marks by finding a lowest position of the speech signals from the passing zero positions.

11. The method according to claim 1, wherein the step of generating at least a set of pitch marks comprises generating the pitch marks by finding a second low position of the speech signals from the passing zero positions.

12. The method according to claim 1, wherein the step of generating at least a set of pitch marks comprises generating the pitch marks by finding a highest and a second high position of the speech signals from the passing zero positions.

13. The method according to claim 1, wherein the step of generating at least a set of pitch marks comprises generating the pitch marks by finding a lowest and a second low position of the speech signals from the passing zero positions.

14. The method according to claim 12, wherein the step of generating at least a set of pitch marks further comprises generating the pitch marks by finding a second high position of the speech signals from the passing zero positions.

15. The method according to claim 1 further comprising the step of estimating at least the set of pitch marks to generate a set of pitch marks.

16. The method according to claim 2 further comprising the step of estimating at least the set of pitch marks to generate a set of pitch marks.

17. The method according to claim 14 further comprising the step of estimating at least the set of pitch marks to generate a set of pitch marks.

18. The method according to claim 15, wherein the step of estimating at least the set of pitch marks comprises respectively calculating an aggregate error of each set of hitch marks, and then generating a corresponding set of pitch marks with a smallest aggregate error.

19. The method according to claim 17, wherein the step of estimating at least the set of pitch marks comprises respectively calculating an aggregate error of each set of hitch marks, and then generating a corresponding set of pitch marks with a smallest aggregate error.

20. The method according to claim 19, wherein calculating the aggregate error is by separately calculating an aggregate error of the wave peak of the speech signals and an aggregate error of the wave trough of the speech signals.

21. The method according to claim 20, wherein the aggregate error of the wave peak is a sum of the following in each predicted period:

a amplitude ratio of the lowest wave trough and the highest wave peak of the speech signals, a amplitude ratio of the second high wave peak and the highest wave peak of the speech signals, and an error between a wave-peak period and the predicted period.

22. The method according to claim 21, wherein the wave-peak period is the distance between two wave-peak pitch marks.

23. The method according to claim 20, wherein the aggregate error of the wave trough is a sum of the following in each predicted period:

a amplitude ratio of the highest wave peak and the lowest wave trough of the speech signals, a amplitude ratio of the second low wave trough and the lowest wave trough of the speech signals, and an error between a wave-trough period and the predicted period.

24. The method according to claim 21, wherein the aggregate error of the wave trough is a sum of the following in each predicted period:

a amplitude ratio of the highest wave peak and the lowest wave trough of the speech signals, a amplitude ratio of the second low wave trough and the lowest wave trough of the speech signals, and an error between a wave-trough period and the predicted period.

25. The method according to claim 23, wherein the wave-trough period is the distance between two wave-trough pitch marks.

26. The method according to claim 24, wherein the predicted period is the distance between a passing zero point and a passing zero point after the next passing zero point.