F. Zussa
Q. Lin
G. Richard
D. Sinder
J. Flanagan
CAIP Ctr., Rutgers Univ., Piscataway, NJ 08855-1390
A new design is presented for open-loop estimation of articulatory parameters from an acoustic speech signal. Previous systems for acoustic-to-articulatory mapping generally involve an optimization loop which adapts synthetic speech to an arbitrary speech input. The open-loop method (i.e., without any optimization), aims to provide an accurate estimation of articulatory parameters at a low computational cost. The technique is used as a component of an adaptive voice mimic system. Model shapes corresponding to the natural signal are found by searching a precomputed table. The table associates vocal tract shapes to their corresponding spectra obtained by linear acoustic simulation. A new metric based on poles from linear predictive analysis is proposed to compare the natural spectrum to the precomputed synthetic spectra. Nearly real-time processing is achieved on a workstation by introducing a two-step search strategy. The resulting representation is known to provide an efficient parametrization of the speech signal which can be used for speech synthesis, low-bit-rate coding, and speech recognition. Further, the open-loop method also provides an accurate initial guess for traditional closed-loop adaptation. Initial results of speech coding using this open-loop estimation are presented and discussed. [Research supported by ARPA-DAST 63-93-C-0064.]