Thesis (MScEng)--University of Stellenbosch, 2002. / ENGLISH ABSTRACT: The topic of this thesis is speaker adaptation, whereby speaker-independent speech models
are adapted to more closely match individual speakers by utilising a small amount of
data from the targeted individual. Speaker adaptation methods - specifically, the MAP,
MLLR and MLED speaker adaptation methods - are critically evaluated and compared.
Two novel extensions of the MLED adaptation method are introduced, derived and
evaluated. The first incorporates the explicit modelling of the mean speaker model in
the speaker-space into the MLED framework. The second extends MLED to use basis
vectors modelling inter-class variance for classes of speech models, instead of basis vectors
modelling inter-speaker variance.
An evaluation of the effect of two different types of feature vector - PLP-cepstra and
LPCCs - on the performance of speaker adaptation is made, to determine which feature
vector is optimal for speaker-independent systems and the adaptation thereof. / AFRIKAANSE OPSOMMING: Die onderwerp van hierdie tesis is spreker-aanpassing, dit wil sê, die verandering van
'n spreker-onafhanklike spraakmodel om nader aan 'n spreker-afhanklike model vir 'n
individu te wees, gegewe 'n klein hoeveelheid spraakdata van die individu. Die volgende
sprekeraanpassing-metodes word geëvalueer: MAP, MLLR en MLED.
Twee nuwe uitbreidings vir die MLED-metode word beskryf, afgelei en geëvalueer.
Die eerste inkorporeer die eksplisiete modellering van die gemiddelde sprekermodel van
die sprekerruimte in die MLED metode. Die tweede uitbreiding maak gebruik van basisvektore
vir MLED wat vanaf die interklas-variansie tussen 'n stel sprekerklasse in plaas
van die interspreker-variansie afgelei is.
Die effek van twee tipes kenmerk-vektore - PLP-kepstra en LPCC's - op die prestasie
van sprekeraanpassings-metodes word ondersoek, sodat die optimale tipe kenmerk-vektor
vir spreker-onafhanklike modelle en hul aanpassing gevind kan word.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/52653 |
| Date | 12 1900 |
| Creators | Fanner, Robert M. |
| Contributors | Du Preez, J. A., Stellenbosch University. Faculty of Engineering. Dept. of Electrical and Electronic Engineering |
| Publisher | Stellenbosch : Stellenbosch University |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | Unknown |
| Type | Thesis |
| Format | 236 p. : ill. |
| Rights | Stellenbosch University |
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