Document Type	Master's Dissertation
Author	Van Leeuwen, Gysbert Floris Van Beek
URN	etd-11172005-090624
Document Title	A Speech recognition-based telephone auto-attendant
Degree	MEng (Computer Engineering)
Department	Electrical, Electronic and Computer Engineering
Supervisor	Advisor Name Title Prof E C Botha Committee Chair
Keywords	telephone answering services automation automatic speech recognition
Date	2002-04-01
Availability	unrestricted
Abstract This dissertation details the implementation of a real-time, speaker-independent telephone auto attendant from first principles on limited quality speech data. An auto attendant is a computerized agent that answers the phone and switches the caller through to the desired person's extension after conducting a limited dialogue to determine the wishes of the caller, through the use of speech recognition technology. The platform is a computer with a telephone interface card. The speech recognition engine uses whole word hidden Markov modelling, with limited vocabulary and constrained (finite state) grammar. The feature set used is based on Mel frequency spaced cepstral coefficients. The Viterbi search is used together with the level building algorithm to recognise speech within the utterances. Word-spotting techniques including a "garbage" model, are used. Various techniques compensating for noise and a varying channel transfer function are employed to improve the recognition rate. An Afrikaans conversational interface prompts the caller for information. Detailed experiments illustrate the dependence and sensitivity of the system on its parameters, and show the influence of several techniques aimed at improving the recognition rate. © 2001, University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. Please cite as follows: Van Leeuwen, GFvB 2001, A speech recognition-based telephone auto-attendant, MEng dissertation, University of Pretoria, Pretoria, viewed yymmdd < http://upetd.up.ac.za/thesis/available/etd-11172005-090624/ > H549/ag
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