Unit selection module and method for Chinese text-to-speech synthesis

• US 20060095264A1
• Filed: 07/22/2005
• Published: 05/04/2006
• Est. Priority Date: 11/04/2004
• Status: Active Grant

• Current Assignee: National Cheng KUNG University (Government of The Republic of China)
• Original Assignee: National Cheng KUNG University (Government of The Republic of China)
• Inventors: Wu, Chung-Hsien, Hsia, Chi-Chun, Wang, Jhing-Fa, Chen, Jiun-Fu
• Granted Patent: US 7,574,360 B2
• Time in Patent Office: Days
• US Class Current: 704/260
• CPC Class Codes: G10L 13/06 Elementary speech units used in speech synthesisers; Concatenation rules

Abstract

This invention relates to a unit selection module for Chinese Text-to-Speech (TTS) synthesis, mainly comprising a probabilistic context free grammar (PCFG) parser, a latent semantic indexing (LSI) module, and a modified variable-length unit selection scheme; any Chinese sentence is firstly input and then parsed into a context-free grammar (CFG) by the PCFG parser; wherein there are several possible CFGs for every Chinese sentence, and the CFG (or the syntactic structure) with the highest probability is then taken as the best CFG (or the syntactic structure) of the Chinese sentence; the LSI module is then used to calculate the structural distance between all the candidate synthesis units and the target unit in a corpus; through the modified variable-length unit selection scheme, tagged with the dynamic programming algorithm, the units are searched to find the best synthesis unit concatenation sequence.

Claims

1. A Chinese Text-To-Speech (TTS) synthesis system comprising:

a word pre-processing module,

a unit selection module,

a speech generation module, and

a corpus;

characterized in that;

said unit selection module comprises;

a probabilistic context free grammar (PCFG) parser, a latent semantic indexing (LSI) module, and a modified variable-length unit selection scheme;

said PCFG parser parses a Chinese sentence to obtain the CFG of said Chinese sentence as its target unit;

said LSI module estimates the structural distance between the candidate synthesis units and the target unit in said corpus; and

through said modified variable-length unit selection scheme, tagged with a dynamic program algorithm, the units are searched to find the best synthesis unit concatenation sequence of said Chinese sentence.

2. The Chinese Text-To-Speech (TTS) synthesis system as claimed in claim 1, wherein said word pre-processing module comprises:

word input processing and text format pre-processing.

3. The Chinese Text-To-Speech (TTS) synthesis system as claimed in claim 1, wherein said corpus comprises Chinese sentences having a large number of vocabulary and their corresponding sound files.

4. The Chinese Text-To-Speech (TTS) synthesis system as claimed in claim 1, wherein said corpus comprises Chinese sentences having a large number of vocabulary and the parallel corpus corresponding to the speech of said Chinese sentences.

5. The Chinese Text-To-Speech (TTS) synthesis system as claimed in claim 1, further comprising:

an automatic speech unit-parsing module, which automatically labels the location of the nodes of every syllable of the Chinese sentence by means of the speech-parsing module.

6. The Chinese Text-To-Speech (TTS) synthesis system as claimed in claim 1, wherein said PCFG parser builds the candidate synthesis unit structural trees and the target unit structural tree in said corpus.

7. The Chinese Text-To-Speech (TTS) synthesis system as claimed in claim 6, wherein said LSI module conducts vector processing for the candidate synthesis unit structural trees and the target unit structural tree, to estimate the structural distance between them.

8. The Chinese Text-To-Speech (TTS) synthesis system as claimed in claim 1, wherein said speech generation module generates the best synthesis unit concatenation sequence.

9. A method for Chinese Text-To-Speech (TTS) synthesis comprising:

a word pre-processing module,

a unit selection module, and

a speech generation module;

said unit selection procedure comprising the following steps;

parsing the CFG of Chinese sentences after they have been subject to said word pre-processing;

building the target unit structural tree of said CFG;

from a corpus, building a plurality of candidate unit structural trees;

said LSI module is used to estimate the structural distance between the target unit structural tree and said plurality of candidate synthesis unit structural trees; and

said dynamic program algorithm is used to search the units so as to find the best synthesis unit concatenation sequence of said Chinese sentence.

10. The method for Chinese Text-To-Speech (TTS) synthesis as claimed in claim 9, comprising:

an automatic speech unit-parsing module, which automatically labels the location of the nodes of every syllable of the Chinese sentence in said corpus by means of said speech-parsing module.

11. A unit selection module used in the Chinese Text-To-Speech (TTS) synthesis system comprising:

a probabilistic context free grammar (PCFG) parser,

a latent semantic indexing (LSI) module, and

a modified variable-length unit selection scheme;

said PCFG parser parses a Chinese sentence to obtain the CFG of said Chinese sentence as its target unit;

said LSI module estimates the structural distance between the candidate synthesis units and the target unit in said corpus; and

through said modified variable-length unit selection scheme, tagged with a dynamic program algorithm, the units are searched to find the best synthesis unit concatenation sequence of said Chinese sentence.

12. The unit selection module as claimed in claim 11, wherein said PCFG parser builds the candidate synthesis unit structural trees and the target unit structural tree in said corpus.

13. The unit selection module as claimed in claim 12, wherein said LSI module conducts vector processing for the candidate synthesis unit structural trees and the target unit structural tree, to estimate the structural distance between them.

14. The unit selection module as claimed in claim 11, wherein said PCFG parser calculates the plurality of possible CFG probabilities of said Chinese sentence, and then takes the CFG with the highest probability as the target unit.

15. A unit selection method for the Chinese Text-To-Speech (TTS) synthesis system comprising:

parsing the CFG of a Chinese sentence;

building the target unit structural tree of said CFG of said Chinese sentence;

from a corpus, building a plurality of candidate unit structural trees;

said LSI module is used to estimate the structural distance between said target unit structural tree and a plurality of said candidate synthesis unit structural trees; and

said dynamic program algorithm is used to search the units so as to find the best synthesis unit concatenation sequence of said Chinese sentence.

16. The unit selection method as claimed in claim 15, comprising:

the plurality of possible CFG probabilities of said Chinese sentence are calculated, and then the CFG with the highest probability is taken as the target unit.

17. The unit selection method as claimed in claim 15, comprising:

vector processing for the candidate synthesis unit structural trees and the target unit structural tree, to estimate the structural distance between them.