AbstractOur primary mode of communication is via speech. Therefore, any person who has difficulty in producing understandable speech, for whatever reason, is at a great disadvantage. It is the role of the speech therapist to help such people to improve their speech production wherever possible. The aim of this work was to develop a computer-based speech therapy tutor for vowel production. The Tutor would be able to analyse monosyllabic utterances in real-time, extract the vowel portion and match this to a pre-determined template, and display the result with no appreciable delay.
A fully-working prototype has been developed which employs general principles of aircraft tracking in a novel way, to track the coefficients of the quadratic factors of the all-pole linear-prediction model for speech production. It is shown how tracking these parameters can be used to extract extended vowels from a monosyllabic utterance. It is also shown how the algorithm which is used to determine the optimum frame-to-frame tracks can be used to perform template matching. The real plane on which the parameters are tracked, the rs-plane, suffers from non-linear scaling of frequency measures. This leads to poor spectral resolution of the perceptually-important low frequency parameters. To overcome this problem, the rs-plane can be warped in order that distance measures taken between points on the plane are more meaningful perceptually.
The Tutor is based on a personal computer (PC). In order that real-time operation can be achieved, the processing power of the PC is enhanced by the addition of a digital signal processor (TMS32020) board and a transputer (T800) board.
The prototype Tutor was developed with help and advice from Dundee Speech Therapy Service, Tayside Health Board, who also conducted a short pilot study of the Tutor.
|Date of Award||Sep 1991|