Estimation of vocal-tract shapes from acoustical analysis of the speech wave: The state of the art

The state of the art of the method for estimating vocal-tract area functions based on the linear prediction of speech is discussed. Limitations and problems involved in this method are: 1) frequency band limitation of the signal, 2) source characteristics, 3) boundary conditions, 4) energy losses within the vocal tract, 5) vocal-tract length estimation, 6) dynamics of the vocal tract, and 7) evaluation of the method [1]. The proposed solutions for these problems are discussed together with some of the current developments pertaining to these problems. Advantages and disadvantages of this method are also discussed in comparison with the lip impulse response method.