Analysis of vocal tract lip reflectance by linear prediction

A simple expression of the vocal tract lip reflectance is derived by use of the well-known equivalence between the Kelly-Lochbaum model of the vocal tract and the linear prediction model of speech. The lip reflectance is described by an ARMA filter with a particular structure, all-pass in the lossless case, involving some attenuation at the formant frequencies in a lossy case. Identification of the ARMA coefficients leads to a new method for the reconstruction of vocal tract area functions.