Determination of Articulatory Parameters from the Speech Signal
Bishnu Saroop Atal, J. E. Hartman · The Journal of the Acoustical Society of America · 1972
A speech analysis method is presented for obtaining a description of the vocal-tract shape in terms of articulatory parameters. A slightly modified version of the Stevens and House three-parameter articulatory model is used to specify the area function of the vocal tract. The area function is described by five parameters, namely, the area at the place of maximum constriction, the area of the lip opening, the length of the lip section, and the length of the vocal tract. Two additional parameters are used to characterize the source. Considering the vocal tract as a lossy acoustic tube, the parameters of a 12th order linear predictor for the synthetic speech signal at the output of the tube are obtained. The parameters so obtained are used to predict the current value of a speech sample by forming a linear combination of the preceding 12 samples of natural speech. The mean-squared difference between these predicted values and the actual sample values in natural speech is minimized by iteratively adjusting the seven vocal-tract and source parameters. The parameter values that minimize the error are finally used to describe the vocal-tract shape.