A parametric monophone speech synthesis system
Date
2006-12
Authors
Klompje, Gideon
Journal Title
Journal ISSN
Volume Title
Publisher
Stellenbosch : University of Stellenbosch
Abstract
Speech is the primary and most natural means of communication between human beings.
With the rapid spread of technology across the globe and the increased number of personal
and public applications for digital equipment in recent years, the need for human/machine
interaction has increased dramatically. Synthetic speech is audible speech produced by a
machine automatically. A text-to-speech (TTS) system is one that converts bodies of text
into digital speech signals which can be heard and understood by a person.
Current TTS systems generally require large annotated speech corpora in the languages
for which they are developed. For many languages these resources are not available. In their
absence, a TTS system generates synthetic speech by means of mathematical algorithms
constrained by certain rules.
This thesis describes the design and implementation of a rule-based speech generation
algorithm for use in a TTS system. The system allows the type, emphasis, pitch and other
parameters associated with a sound and its particular mode of articulation to be specified.
However, no attempt is made to model prosodic and other higher-level information. Instead,
this is assumed known. The algorithm uses linear predictive (LP) models of monophone
speech units, which greatly reduces the amount of data required for development in a new
language. A novel approach to the interpolation of monophone speech units is presented
to allow realistic transitions between monophone units. Additionally, novel algorithms for
estimation and modelling of the harmonic and stochastic content of an excitation signal are
presented. This is used to determine the amount of voiced and unvoiced energy present in
individual speech sounds.
Promising results were obtained when evaluating the developed system’s South African
English speech output using two widely used speech intelligibility tests, namely the modified
rhyme test (MRT) and semantically unpredictable sentences (SUS).
Description
Thesis (MScEng (Electrical and Electronic Engineering))--University of Stellenbosch, 2006.
Keywords
Excitation signal modelling, LPC synthesis, Monophone synthesis, Multi-lingual speech synthesis, Rule-based speech synthesis, Speech signal modelling, Speech synthesis, Dissertations -- Electronic engineering, Theses -- Electronic engineering