The University of Southampton
University of Southampton Institutional Repository

The Development of an Enhanced Electropalatography System for Speech research

Chiu, W.S.C. and Shadle, C. (1995) The Development of an Enhanced Electropalatography System for Speech research University of Southampton, : University of Southampton, Doctoral Thesis .

Record type: Thesis (Doctoral)


To understand how speech is produced by individual human beings, it is fundamentally important to be able to determine exactly the three-dimensional shape of the vocal tract. The vocal tract is inaccessible so its exact form is difficult to determine with live subjects. There is a wide variety of methods that provide information on the vocal tract shape. The technique of Electropalatography (EPG) is cheap, relatively simple, non-invasive and highly informative. Using EPG on its own, it is possible to deduce information about the shape, movement and position of tongue-palate contact during continuous speech. However, data provided by EPG is in the form of a two-dimensional representation in which all absolute positional information is lost. This thesis describe the development of an enhanced Electropalatography (eEPG) system, which retains most of the advantages of EPG while overcoming some of the disadvantages by representing the three-dimensional (3D) shape of the palate. The eEPG system uses digitised palate shape data to display the tongue-palate contact pattern in 3D. The 3D palate shape is displayed on a Silicon Graphics workstation as a surface made up of polygons represented by a quadrilateral mesh. EPG contact patterns are superimposed onto the 3D palate shape by displaying the relevant polygons in a different colour. By using this system, differences in shape between individual palates, apparent on visual inspection of the actual palates, are also apparent in the image on screen. The contact patterns can be related more easily to articulatory features such as the alveolar ridge since the ridge is visible on the 3D display. Further, methods have been devised for computing absolute distances along paths lying on the palate surface. Combining this with calibrated palate shape data allows measurements accurate to 1 mm to be made between contact locations on the palate shape. These have been validated with manual measurements. The sampling rate for EPG is 100Hz and the data rate is equivalent to 62 bits per 10ms. In the past few years, some coding (parameterization) methods have been introduced to try to reduce the amount of data while retaining the important aspects. Feature coding methods are proposed here and several parameters are investigated, expressed in terms of both conventional measures such as row number, and in absolute measures of distance and area (i.e. mm and mm2). Features studied include location of constriction and degree of constriction. Finally, in order to reduce the amount of data while retaining the spatial information, composite frames that represent a series of EPG frames are computed. Measures of goodness of the composite frames that do and do not use 3D data are described. Some example are given in which fricative data has been processed by generating a composite frame for the entire fricative, and computing an area estimate for each row of the composite frame using the assumption of a flat tongue. This thesis demonstrates the current capability and inherent flexibility of the enhanced electropalatography system. In the future, the eEPG system can be extended to compute volume estimates again using a flat tongue model. By incorporating information on the tongue surface provided by other imaging methods such as ultrasound, more accurate area and volume estimates can be obtained.

Full text not available from this repository.

More information

Published date: 1995
Additional Information: Address: Faculty of Engineering and Applied Science
Organisations: University of Southampton, Electronics & Computer Science


Local EPrints ID: 250160
PURE UUID: b95b095c-f7b0-4b69-8698-d17cef0155ed

Catalogue record

Date deposited: 04 May 1999
Last modified: 18 Jul 2017 10:43

Export record


Author: W.S.C. Chiu
Author: C. Shadle

University divisions

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton:

ePrints Soton supports OAI 2.0 with a base URL of

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.