Use of optical distance sensing to track tongue motion

C. K. Chuang, William Shi Yuan Wang

Research output: Journal article publicationJournal articleAcademic researchpeer-review

29 Citations (Scopus)


The authors have designed a device that uses a reflected-light-sensing technique to monitor tongue movement in the frontal oral cavity. The sensing unit is composed of a LED light source and a phototransistor, mounted together onto an artificial palate, and attached to the hard palate. The basic sensing function of this unit is governed by the formula r/(r2+ x(o)2)(3/2) rather than by the inverse square distance law. In this equation, r is the distance between the sensor and the reflector, namely, the tongue surface. The x(o) is the separation between the source and the photosensor. Two potential problems, the beam dispersion effect of the light source and the nonparallel movement of the tongue, were anticipated. They can be theoretically represented or technically prevented. The softness of the tongue and the protuberances of its surface are also favorable aspects of this method, creating special light reflection from the tongue surface. The available output function was from 0 to 40 or 50 mm. This gives the device the capability of detecting both vowel and consonantal articulation. The method can be useful to further speech research and the development of a language teaching aid system.
Original languageEnglish
Pages (from-to)482-496
Number of pages15
JournalJournal of Speech and Hearing Research
Issue number3
Publication statusPublished - 1 Dec 1978
Externally publishedYes

ASJC Scopus subject areas

  • Otorhinolaryngology


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