Stochastic modeling of spectral adjustment for high quality pitch modification
AssigneeAT&T Corp.
InventorsIoannis G. Stylianou, Alexander Kain
Life of this patent
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Abstract
Natural-sounding synthesized speech is obtained from pieced elemental speech units that have their super-class identities known (e.g. phoneme type), and their line spectral frequencies (LSF) set in accordance with a correlation between the desired fundamental frequency and the LSF vectors that are known for different classes in the super-class. The correlation between a fundamental frequency in a class and the corresponding LSF is obtained by, for example, analyzing the database of recorded speech of a person and, more particularly, by analyzing frames of the speech signal.
Claims20
A method for generating a speech signal comprising the steps of:
- receiving super-class information;
- receiving fundamental frequency information;
- applying each tuple of super-class information and fundamental frequency information to a module that correlates fundamental frequencies with LSF vectors for different super-classes, to obtain a desired LSF vector associated with each of said tuples;
- and
- generating a speech spectrum, in association with each tuple, that is characterized by an LSF vector that is, or approximates, said desired LSF vector associated with each of said tuples.
A method for generating a speech signal comprising the steps of:
- receiving a group of speech samples for a speech frame;
- receiving fundamental frequency information for said speech frame;
- associating super-class information with said speech frame;
- applying said super-class information and said fundamental frequency information to a module that correlates fundamental frequencies with LSF vectors for different super-classes, to obtain from said module a desired LSF vector of coefficients associated with each of said tuples;
- and
- modifying said group of speech samples to create a group of modified speech samples, such that said group of modified speech samples has a spectrum envelope whose LSF vector approximates said desired LSF vector.
A method for generating a speech signal comprising the steps of:
- receiving fundamental frequency information for a speech frame;
- associating super-class information with said speech frame;
- applying said super-class information and said fundamental frequency information to a module that correlates fundamental frequencies with LSF vectors for different super-classes, to obtain from said module a desired LSF vector of coefficients associated with each of said tuples;
- and
- modifying said group of speech samples to create a group of modified speech samples, such that said group of modified speech samples has a spectrum envelope whose LSF vector approximates said desired LSF vector.
A method for communicating information from a transmitter to a receiver comprising the steps of, in the transmitter:
- receiving a speech signal;
- subdividing said speech signal into phoneme-related segments;
- subdividing each of said segments into a plurality of speech frames;
- analyzing each frame of said speech frames identify at least fundamental frequency of speech in said frame, and energy in said frame;
- and
- transmitting said information that specifies said fundamental frequency and said energy, and
- at least for some of said speech frames, those being selected speech frames, transmitting information about super-class identities of the phoneme-related segments from which said selected speech frames are subdivided.
Dependencies are inferred from the claim text.