A warped time-frequency expansion for speech signal representation

A novel representation for speech signals is proposed. The time-varying frequency content of a speech segment is represented as a weighted sum of two-dimensional basis vectors; these incorporate both frequency warping and frequency-dependent time warping. This is quite flexible; for example, any arbitrary time or frequency warping function can easily be implemented, and any time-frequency representation can be used as the starting point. Examples are presented which demonstrate desirable characteristics of the representation: (1) explicit quantification of parameter trajectories, (2) time resolution which varies with respect to time and frequency, and (3) the ability to reconstruct a time-frequency plot which reflects the resolution characteristics of the representation.<
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