SPEECH SYNTHESIS APPARATUS AND METHOD

• US 20110087488A1
• Filed: 12/16/2010
• Published: 04/14/2011
• Est. Priority Date: 03/25/2009
• Status: Active Grant

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Morinaka, Ryo, Kagoshima, Takehiko
• Granted Patent: US 9,002,711 B2
• Time in Patent Office: Days
• US Class Current: 704/207
• CPC Class Codes: G10L 13/033 Voice editing, e.g. manipulating the voice of the synthesiser
• CPC Class Codes: G10L 13/06 Elementary speech units used in speech synthesisers; Concatenation rules
• CPC Class Codes: G10L 19/097 using prototype waveform decomposition or prototype waveform interpolative [PWI] coders
• CPC Class Codes: G10L 2021/0135 Voice conversion or morphing
• CPC Class Codes: G10L 25/15 the extracted parameters being formant information

Abstract

According to an embodiment, a speech synthesis apparatus includes a selecting unit configured to select speaker'"'"'s parameters one by one for respective speakers and obtain a plurality of speakers'"'"' parameters, the speaker'"'"'s parameters being prepared for respective pitch waveforms corresponding to speaker'"'"'s speech sounds, the speaker'"'"'s parameters including formant frequencies, formant phases, formant powers, and window functions concerning respective formants that are contained in the respective pitch waveforms. The apparatus includes a mapping unit configured to make formants correspond to each other between the plurality of speakers'"'"' parameters using a cost function based on the formant frequencies and the formant powers. The apparatus includes a generating unit configured to generate an interpolated speaker'"'"'s parameter by interpolating, at desired interpolation ratios, the formant frequencies, formant phases, formant powers, and window functions of formants which are made to correspond to each other.

Claims

1. A speech synthesis apparatus comprising:

a selecting unit configured to select speaker'"'"'s parameters one by one for respective speakers and obtain a plurality of speakers'"'"' parameters, the speaker'"'"'s parameters being prepared for respective pitch waveforms corresponding to speaker'"'"'s speech sounds, the speaker'"'"'s parameters including formant frequencies, formant phases, formant powers, and window functions concerning respective formants that are contained in the respective pitch waveforms;

a mapping unit configured to make formants correspond to each other between the plurality of speakers'"'"' parameters using a cost function based on the formant frequencies and the formant powers;

a generating unit configured to generate an interpolated speaker'"'"'s parameter by interpolating, at desired interpolation ratios, the formant frequencies, formant phases, formant powers, and window functions of formants which are made to correspond to each other; and

a synthesizing unit configured to synthesize a pitch waveform corresponding to interpolated speaker'"'"'s speech sounds based on the interpolation ratios using the interpolated speaker'"'"'s parameter.

2. The apparatus according to claim 1, wherein

the cost function is a weighted sum of a difference between the formant frequencies and a difference between the formant powers.

3. The apparatus according to claim 1, wherein

the generating unit inserts, into the interpolated speaker'"'"'s parameter, a formant frequency, a formant phase, a formant power, and a window function concerning a formant which is not corresponded to other formants.

4. The apparatus according to claim 1, wherein

the speaker'"'"'s parameters are prepared for respective pitch waveforms corresponding to periodic components of speaker'"'"'s speech sounds,

the synthesizing unit synthesizes a pitch waveform corresponding to a periodic component of the interpolated speaker'"'"'s speech sound using the interpolated speaker'"'"'s parameter, and

the apparatus further comprises

a second selecting unit configured to select, one by one for respective speakers, pitch waveforms corresponding to aperiodic components of the speaker'"'"'s speech sounds and obtain a plurality of pitch waveforms,

a second generating unit configured to generate a pitch waveform corresponding to an aperiodic component of the interpolated speaker'"'"'s speech sound by interpolating the plurality of pitch waveforms at the interpolation ratios, and

a second synthesizing unit configured to synthesize the pitch waveform corresponding to the periodic component of the interpolated speaker'"'"'s speech sound and the pitch waveform corresponding to the aperiodic component of the interpolated speaker'"'"'s speech sound, and obtain the pitch waveform corresponding to the interpolated speaker'"'"'s speech sound.

5. The apparatus according to claim 1, wherein

the mapping unit applies, to the formant frequencies, a function for compensating for a difference in vocal tract length between speakers, and then makes formants correspond to each other between the plurality of speakers'"'"' parameters using the cost function.

6. The apparatus according to claim 1, wherein

the mapping unit applies, to the formant powers, a function for compensating for a difference in power between speakers, and then makes formants correspond to each other between the plurality of speakers'"'"' parameters using the cost function.

7. The apparatus according to claim 1, further comprising:

a third generating unit configured to generate a pitch waveform corresponding to target speaker'"'"'s speech sound; and

a calculating unit configured to calculate an optimum interpolation ratio for obtaining the target speaker'"'"'s speech sound based on the plurality of speakers'"'"' parameters, by performing, for the interpolation ratios, feedback control of making the pitch waveform corresponding to the interpolated speaker'"'"'s speech sound come close to the pitch waveform corresponding to the target speaker'"'"'s speech sound.

8. The apparatus according to claim 1, wherein the interpolation ratio is a ratio assigned to the speaker'"'"'s parameter.

9. A non-transitory computer readable storage medium storing instructions of a computer program which when executed by a computer results in performance of steps comprising:

selecting speaker'"'"'s parameters one by one for respective speakers and obtaining a plurality of speakers'"'"' parameters, the speaker'"'"'s parameters being prepared for respective pitch waveforms corresponding to speaker'"'"'s speech sounds, the speaker'"'"'s parameters including formant frequencies, formant phases, formant powers, and window functions concerning respective formants that are contained in the respective pitch waveforms;

making formants correspond to each other between the plurality of speakers'"'"' parameters using a cost function based on the formant frequencies and the formant powers;

generating an interpolated speaker'"'"'s parameter by interpolating, at desired interpolation ratios, the formant frequencies, formant phases, formant powers, and window functions of formants which are made to correspond to each other; and

synthesizing a pitch waveform corresponding to interpolated speaker'"'"'s speech sounds based on the interpolation ratios using the interpolated speaker'"'"'s parameter.

10. A speech synthesis method comprising:

selecting speaker'"'"'s parameters one by one for respective speakers and obtaining a plurality of speakers'"'"' parameters, by a selecting unit, the speaker'"'"'s parameters being prepared for respective pitch waveforms corresponding to speaker'"'"'s speech sounds, the speaker'"'"'s parameters including formant frequencies, formant phases, formant powers, and window functions concerning respective formants that are contained in the respective pitch waveforms;

making formants correspond to each other between the plurality of speakers'"'"' parameters using a cost function based on the formant frequencies and the formant powers, by a mapping unit;

generating an interpolated speaker'"'"'s parameter by interpolating, at desired interpolation ratios, the formant frequencies, formant phases, formant powers, and window functions of formants which are made to correspond to each other, by a generating unit; and

synthesizing a pitch waveform corresponding to interpolated speaker'"'"'s speech sounds based on the interpolation ratios using the interpolated speaker'"'"'s parameter, by a synthesis unit.