Patent ID: 7630896

Claim:
A speech synthesis system for generating synthesized speech by segmenting a phonetic sequence derived from an input text by predetermined synthesis units, and by concatenation of representative speech units each of which is extracted from respective one of the synthesis units, the system comprising: a storage unit configured to store a plurality of speech units corresponding to the synthesis units; a selector configured to select, with respect to each of the synthesis units of the phonetic sequence derived from the input text, N speech units and M speech units (N<M) in an order corresponding to a smaller cost calculated by a cost function, respectively, from those speech units stored in the storage unit, based on a result of the cost function indicating a level of distortion of the synthesized speech; a representative speech generator configured to generate the representative speech unit corresponding to the synthesis unit by calculating a statistics of power information from the M selected speech units, and by fusing the N speech units so as to increase the synthesized speech in quality by carrying out at least one of correction of the power information based on the statistics of the power information, weight assignment based on the power information, and removal of the speech unit based on the power information; and a speech waveform generator configured to generate a speech waveform by concatenating the generated representative speech units, the cost function being a function represented by a weighted sum of plural sub-cost functions, and each of the sub-cost functions being one for calculating the cost needed to estimate a level of distortion with respect to a target speech of the synthesized speech that occurs when the synthesized speech is generated by using the speech units stored in the storage unit.