PERIODIC SIGNAL PROCESSING METHOD,PERIODIC SIGNAL CONVERSION METHOD,PERIODIC SIGNAL PROCESSING DEVICE, AND PERIODIC SIGNAL ANALYSIS METHOD

• US 20110015931A1
• Filed: 07/18/2008
• Published: 01/20/2011
• Est. Priority Date: 07/18/2007
• Status: Active Grant

• Current Assignee: Wakayama University
• Original Assignee: Wakayama University
• Inventors: Kawahara, Hideki, Morise, Masanori, Irino, Toshio, Takahashi, Toru
• Granted Patent: US 8,781,819 B2
• Time in Patent Office: Days
• US Class Current: 704/264
• CPC Class Codes: G10L 13/033 Voice editing, e.g. manipulating the voice of the synthesiser
• CPC Class Codes: G10L 13/04 Details of speech synthesis systems, e.g. synthesiser structure or memory management
• CPC Class Codes: G10L 21/00 Speech or voice signal processing techniques to produce another audible or non-audible signal, e.g. visual or tactile, in order to modify its quality or its intelligibility G10L19/00 takes precedence
• CPC Class Codes: G10L 25/00 Speech or voice analysis techniques not restricted to a single one of groups G10L15/00 - G10L21/00 muting semiconductor-based amplifiers when some special characteristics of a signal are sensed by a speech detector, e.g. sensing when no signal is present, H03G3/34
• CPC Class Codes: G10L 25/90 Pitch determination of speech signals

Abstract

The invention relates to a periodic signal processing method, a periodic signal conversion method, and a periodic signal processing device capable of reducing the influence of periodicity without using a spectral model. Time windows are arranged such that a center of each of the time windows is at a division position which divides a fundamental frequency in a temporal direction into fractions 1/n (where n is an integer equal to or larger than 2) so as to extract a plurality of portions of different ranges from a signal having periodicity. A power spectrum for the plurality of portions extracted by the respective time windows is calculated, and the calculated power spectrum is added with a same ratio.

Claims

1. A periodic signal processing method comprising:

arranging time windows such that a center of each of the time windows is at a division position which divides a fundamental frequency in a temporal direction into fractions 1/n (where n is an integer equal to or larger than

     2) so as to extract a plurality of portions of different ranges from a signal having periodicity;

calculating a power spectrum for the plurality of portions extracted by the respective time windows; and

adding the calculated power spectrum with a same ratio to obtain a first power spectrum.

2. The periodic signal processing method of claim 1, comprising convolving a rectangular smoothing function having a width corresponding to a fundamental period in a frequency direction on the obtained first power spectrum.

3. The periodic signal processing method of claim 1, comprising:

calculating a cumulative sum of the first power spectra for every predetermined range in the frequency direction, and

calculating a difference in the cumulative sum of the power spectra in the predetermined range between two points at a predetermined interval in the frequency direction and performing linear interpolation to obtain a smoothed power spectrum.

4. The periodic signal processing method of claim 3, wherein the smoothed power spectrum obtained by the linear interpolation is subjected to logarithmic transformation, predetermined correction, and exponential transformation.

5. A periodic signal analysis method, comprising:

dividing a first power spectrum obtained by the periodic signal processing method of claim 2, by a second power spectrum obtained by convolving a rectangular smoothing function having a width corresponding to a fundamental period in a frequency direction;

obtaining a deviation spectrum with only a component due to periodicity obtained by subtracting 1 from a result obtained by the division of the first power spectrum; and

obtaining a value of the fundamental period by calculating a weighted Fourier transform.

6. A periodic signal analysis method, comprising:

contracting/dilating a time axis with a ratio in inverse proportion to an instantaneous frequency of a frequency of a fundamental period; and

, for a signal having periodicity converted so as to apparently become a signal having a frequency of a predetermined fundamental period, calculating a ratio of a periodic component in the signal as an absolute value of a signal, which is obtained by convolving a quadrature signal designed using a frequency of a fundamental period set in advance on a deviation spectrum with only a component due to periodicity obtained by subtracting 1 from a result obtained by dividing the first power spectrum of claim 1 by the second power spectrum of claim 2, so as to calculate a ratio of an aperiodic component in the signal.

7. A periodic signal conversion method of converting the periodic signal into a different signal by using a spectrum obtained by the periodic signal processing method of claim 1.

9. A periodic signal analysis method, comprising:

dividing a first power spectrum obtained by the periodic signal processing method of claim 3, by a second power spectrum obtained by convolving a rectangular smoothing function having a width corresponding to a fundamental period in a frequency direction;

obtaining a deviation spectrum with only a component due to periodicity obtained by subtracting 1 from a result obtained by the division of the first power spectrum; and

obtaining a value of the fundamental period by calculating a weighted Fourier transform.

10. A periodic signal analysis method, comprising:

dividing a first power spectrum obtained by the periodic signal processing method of claim 4, by a second power spectrum obtained by convolving a rectangular smoothing function having a width corresponding to a fundamental period in a frequency direction;

obtaining a deviation spectrum with only a component due to periodicity obtained by subtracting 1 from a result obtained by the division of the first power spectrum; and

obtaining a value of the fundamental period by calculating a weighted Fourier transform.

11. A periodic signal conversion method of converting the periodic signal into a different signal by using a spectrum obtained by the periodic signal processing method of claim 2.

12. A periodic signal conversion method of converting the periodic signal into a different signal by using a spectrum obtained by the periodic signal processing method of claim 3.

13. A periodic signal conversion method of converting the periodic signal into a different signal by using a spectrum obtained by the periodic signal processing method of claim 4.

8. A periodic signal processing device, comprising:

an extraction unit which arranges time windows such that a center of each of the time windows is at a division position which divides a fundamental frequency in a temporal direction into fractions 1/n (where n is an integer equal to or larger than

     2) so as to extract a plurality of portions of different ranges from a signal having periodicity;

a calculation unit which calculates a power spectrum for the plurality of portions extracted by the respective time windows; and

an addition unit which adds the calculated power spectrum with a same ratio.