Synthesis-based pre-selection of suitable units for concatenative speech
View Patent ↗A method for generating concatenative speech uses a speech synthesis input to populate a triphone-indexed database that is later used for searching and retrieval to create a phoneme string acceptable for a text-to-speech operation. Prior to initiating the “real time” synthesis process, a database is created of all possible triphone contexts by inputting a continuous stream of speech. The speech data is then analyzed to identify all possible triphone sequences in the stream, and the various units chosen for each context. During a later text-to-speech operation, the triphone contexts in the text are identified and the triphone-indexed phonemes in the database are searched to retrieve the best-matched candidates.
1. A method of synthesizing speech from text using a triphone unit selection database, the method comprising:
receiving input text;
selecting a plurality of N phoneme units from the triphone unit selection database as candidate phonemes for synthesized speech based on the input text;
applying a cost process to select a set of phonemes from the candidate phonemes; and
synthesizing speech using the selected set of phonemes.
2. The method as defined in claim 1 wherein a Viterbi search is applied as the cost process.
3. The method as defined in claim 1 wherein subsequent to the step of receiving the input text the following step is performed:
parsing the received text into recognizable units.
4. The method as defined in claim 3 wherein the parsing comprises the steps of:
applying a text normalization process to parse the received text into known words and convert abbreviations into known words; and
applying a syntactic process to perform a grammatical analysis of the known words and identify their associated part of speech.