Machine Lip-Reading of Japanese Vowels Utilizing A Stereoscopic Vision System

Masami Nakano, Tomio Watanabe

Research output: Contribution to journalArticle

1 Citation (Scopus)


The lip-shape recognition of Japanese vowels utilizing a stereoscopic vision system has been performed to enhance the discrimination of five vowels by machine lip-reading. The opening angle P 4 between the upper lip and the lower lip is selected as the typical three-dimensional feature parameter of lip shape, in addition to the usual feature parameters such as the width P 1 and the height P 2 of the lip shape and distance P 3 between the tips of the upper lip and the chin. Compared with the 3 two-dimensional parameters P 1 , P 2 and P 3 used in a single-vision system, the 3 and 4 three-dimensional parameters led to the significant increase of discrimination rate, and in particular, the discrimination rate by the 4 three-dimensional parameters was more than 90% for every tested subject. Recognition for an unspecified subject was also examined, based on the selections of the variance-covariance matrix and the mean vector of feature variables, by which the Mahalanobis' generalized square distance and the maximum likelihood discrimination function were determined.

Original languageEnglish
Pages (from-to)525-530
Number of pages6
Journaltransactions of the japan society of mechanical engineers series c
Issue number570
Publication statusPublished - 1994 Jan 1
Externally publishedYes


  • Human Engineering
  • Lip Reading
  • Lip Shapes
  • Man-Machine Interface
  • Stereoscopic Vision
  • Three-Dimensional Measurement
  • Vowel Recognition

ASJC Scopus subject areas

  • Mechanics of Materials
  • Mechanical Engineering
  • Industrial and Manufacturing Engineering

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