Method and system for preselection of suitable units for concatenative speech
View Patent ↗A system and method for improving the response time of text-to-speech synthesis utilizes “triphone contexts” (i.e., triplets comprising a central phoneme and its immediate context) as the basic unit, instead of performing phoneme-by-phoneme synthesis. The method comprises a method of generating a triphone preselection cost database for use in speech synthesis, the method comprising 1) selecting a triphone sequence u 1 -u 2 -u 3 , 2) calculating a preselection cost for each 5-phoneme sequence u a -u 1 -u 2 -u 3 -u b , where u 2 is allowed to match any identically labeled phoneme in a database and the units u a and u b vary over the entire phoneme universe and 3) storing a group of the selected triphone sequences exhibiting the lowest costs in a triphone preselection cost database.
1. A triphone preselection cost database for use in speech synthesis, the database generated according to a method comprising:
1) selecting a triphone sequence u 1 -u 2 -u 3 ;
2) calculating a preselection cost for each 5-phoneme sequence u a -u 1 -u 2 -u 3 -u b , where u 2 is allowed to match any identically labeled phoneme in a database and the units u a and u b vary over the entire phoneme universe; and
3) storing a group of the selected triphone sequences exhibiting the lowest costs in a triphone preselection cost database by:
a) determining a plurality of N least cost database units for the particular 5-phoneme context;
b) performing the union of the N least cost units for all combinations of u a and u b ;
c) storing the union created in step b) in a triphone preselection cost database; and
d) repeating steps 1)–3) for each possible triphone sequence.
2. The triphone preselection cost database of claim 1 , the method for generating the database farther comprising generating a key to index each triphone in the database.
3. The triphone preselection cost database of claim 1 , wherein a plurality of fifty least costs sequences for any possible 5-phone context are stored.
4. The triphone preselection cost database of claim 1 , wherein the preselection cost is the target cost or an element of the target cost.
5. A computer-readable medium storing a triphone preselection cost database for use in speech synthesis, the database generated according to a method comprising:
1) selecting a triphone sequence u 1 -u 2 -u 3 ;
2) calculating a preselection cost for each 5-phoneme sequence u a -u 1 -u 2 -u 3 -u b , where u 2 is allowed to match any identically labeled phoneme in a database and the units u a and u b vary over the entire phoneme universe; and
3) storing a group of the selected triphone sequences exhibiting the lowest costs in a triphone preselection cost database by:
a) determining a plurality of N least cost database units for the particular 5-phoneme context;
b) performing the union of the N least cost units for all combinations of u a and u b ;
c) storing the union created in step b) in a triphone preselection cost database; and
d) repeating steps 1)–3) for each possible triphone sequence.
6. The computer-readable medium of claim 5 , the method for generating the database further comprising generating a key to index each triphone in the database.
7. The computer-readable medium of claim 5 , wherein a plurality of fifty least costs sequences for any possible 5-phone context are stored.
8. The computer-readable medium of claim 5 , wherein the preselection cost is the target cost or an element of the target cost.
9. A method of generating a triphone preselection cost database for use in speech synthesis, the method comprising:
1) selecting a triphone sequence u 1 -u 2 -u 3 ;
2) calculating a preselection cost for each 5-phoneme sequence u a -u 1 -u 2 -u 3 -u b , where u 2 is allowed to match any identically labeled phoneme in a database and the units u a and u b vary over the entire phoneme universe; and
3) storing a group of the selected triphone sequences exhibiting the lowest costs in a triphone preselection cost database by:
a) determining a plurality of N least cost database units for the particular 5-phoneme context;
b) performing the union of the N least cost units for all combinations of u a and u b ;
c) storing the union created in step b) in a triphone preselection cost database; and
d) repeating steps 1)–3) for each possible triphone sequence.
10. The method of generating a triphone preselection cost database of claim 9 , the method for generating the database further comprising generating a key to index each triphone in the database.
11. The method of generating a triphone preselection cost database of claim 9 , wherein a plurality of fifty least costs sequences for any possible 5-phone context are stored.
12. The method of generating a triphone preselection cost database of claim 9 , wherein the preselection cost is the target cost or an element of the target cost.