Evaluation of a Statistical Approach to Voiced-Unvoiced-Silence Analysis for Telephone-Quality Speech
L. R. Rabiner, Christiane Schmidt, Bishnu Saroop Atal · Bell System Technical Journal · 1977
Recently, a statistical-decision approach to the problem of voiced-unvoiced-silence detection of speech was proposed by Atal and Rabiner. This method was found to perform well on high-quality speech. However, the five speech parameters used in the analysis were not found to be as good for telephone-quality speech. Thus, an investigation was undertaken to determine a suitable set of parameters that would provide a reliable voiced-unvoiced-silence decision across a variety of standard telephone connections. A large number of parameters (70) were included in the investigation, including 12 lpc coefficients, 12 correlation coefficients, 12 parcor coefficients, 12 lpc partial error terms, etc. Many of the parameters were immediately eliminated because they provided almost no separability between the three decision classes. The remaining parameters were used in a knockout optimization to determine the five best parameters to use for a voiced-unvoiced-silence analysis. Various error weights were investigated to see what types of errors occurred and how they could be minimized. Finally, the use of the Itakura two-pole spectral normalization was investigated to see its effect on the error scores.