Comparison of parametric representations for monosyllabic word recognition in continuously spoken sentences

TLDR

The study focused on recognizing many phonetically similar monosyllabic words, emphasizing retention of phonetically significant acoustic information amid syntactic and duration variations. The study compared several parametric acoustic representations for word recognition performance in a syllable‑oriented continuous speech recognition system. Word templates were generated for each parameter set—mel‑frequency cepstrum, linear frequency cepstrum, linear prediction cepstrum, linear prediction spectrum, or reflection coefficients—using efficient dynamic warping, and test data were time‑registered with the templates. Ten mel‑frequency cepstrum coefficients computed every 6.4 ms yielded the best performance, achieving 96.5 % and 95.0 % recognition for two speakers, likely because they better capture perceptually relevant short‑term speech spectrum features.

Abstract

Several parametric representations of the acoustic signal were compared with regard to word recognition performance in a syllable-oriented continuous speech recognition system. The vocabulary included many phonetically similar monosyllabic words, therefore the emphasis was on the ability to retain phonetically significant acoustic information in the face of syntactic and duration variations. For each parameter set (based on a mel-frequency cepstrum, a linear frequency cepstrum, a linear prediction cepstrum, a linear prediction spectrum, or a set of reflection coefficients), word templates were generated using an efficient dynamic warping method, and test data were time registered with the templates. A set of ten mel-frequency cepstrum coefficients computed every 6.4 ms resulted in the best performance, namely 96.5 percent and 95.0 percent recognition with each of two speakers. The superior performance of the mel-frequency cepstrum coefficients may be attributed to the fact that they better represent the perceptually relevant aspects of the short-term speech spectrum.