Atext to Spechconverter

8/3/2019 Atext to Spechconverter

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A TextA Text--toto--Speech Synthesis SystemSpeech Synthesis System

Presented By:

Michael Beddaoui

Abdel-Aziz El-Solh


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Presentation OutlinePresentation Outline Introduction

Background

3 Components of TTS System Text Pre-processing Aziz

Prosody Mike

Concatenation Mike

Summary What has been done / Future Work

Conclusion

Questions


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What is a TTS System?What is a TTS System?Definition:

A system which takes as input a sequence of words and

converts them to speech

Applications:

Services for the hearing impaired

Reading email aloud

Commercial TTS Systems:

Festival

Bell Labs TTS


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Different TTS SystemsDifferent TTS Systems

Phonemes are: The minimal distinctive phonetic units

Relatively small in number (39 phonemes in

English)

Disadvantage:

Phonemes ignore transitional sound !!!

Phoneme-Based TTS System


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Different TTS Systems (contd)Different TTS Systems (contd)

Disadvantage:

Over 1500 diphones in the English language !!!

Diphone-Based TTS System

Diphones are: Made up of 2 phonemes

Incorporate transitional sound

Make for better sounding speech


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TTS System

Fundamental ComponentsFundamental Components

Text

Pre-processingProsody Concatenation

words


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Text PreText Pre--ProcessingProcessing Input

String of characters (sentence)

Output String of diphone symbols

Objective

Perform sentence level analysis Punctuation marks

Pauses between words

Convert all input to corresponding diphones


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Text PreText Pre--Processing (BlockDiagram)Processing (BlockDiagram)

WordSegmenterAcronymConverterNumberConverter

W

ord toDiphone

Translator(Phonetization)

Diphone

Dictionary

MLDSNumberConverter


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Number ConverterNumber Converter Replace numerals with their textual

versions

100 one hundred

Handle fractional and decimal

numbers

0.25 point two five


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Word to

Diphone


Diphone

Dictionary

MLDSAcronymConverter


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Acronym ConverterAcronym Converter Replace acronyms with single letter

components

A.B.C. A B C

Change abbreviations to full textual

format

Mr. Mister


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Word to

Diphone


Diphone

Dictionary

MLDS

WordSegmenter


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Word SegmenterWord Segmenter Divide sentence into word segments

Special delimiter to separate segments

(i.e. ||)

Segments can be:

A single word

An acronym

A numeral

Identify punctuation marks


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W

ordSegmenterAcronymConverterNumberConverter

Word to

Diphone


Diphone

Dictionary

MLDS

Word to

Diphone



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Word To Diphone ConverterWord To Diphone Converter

(Phonetization)(Phonetization) Purpose

Translate words to their diphone

representations

Resource

Dictionary of words and their diphones

(derived from CMU phoneme database)Over 175,000 words supported


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WW--toto--D Converter ContdD Converter Contd Implementation

Binary Search Algorithm in C

Start with whole dictionary as search rangestart index, end index, middle index

If target word alphabetically less then middleword,

then ignore second half (i.e. end index =middle index)

else ignore first half (i.e. start index = middleindex)

Repeat until word found or range contains zero

words


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WW--toto--D Converter ContdD Converter Contd Advantages

Fast search times

Search range decreases exponentially with

each iteration (max of 1 sec currently)

Less complicated to implement

Compared to indexing dictionary or

Importing the dictionary to an internal

structure


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W

ordSegmenter

Acronym

Converter

Number

Converter

Word to

Diphone


Diphone

Dictionary

MLDSMLDS


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The MultiThe Multi--Level Data StructureLevel Data Structure Contains all necessary data for the

next sub-system:

Word

Diphone representation

Prosodic parameters for each diphone

This reflects both word-level and sentence-level prosody

Allows for modularization


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ProsodyProsody

DiphoneRetrieval

ConcatenationAcousticManipulation

Diphone

Database

MLDS

done

yes

no


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Diphone RetrievalDiphone Retrieval Database of recorded diphones

Every diphone matched with txt file

Distinguished by type (CC, CV, VC, VV)

References to specific components

within waveform

Store diphone waveform andprosodic parameters in variables


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Properties of Speech SignalsProperties of Speech Signals

c a t

PeriodicNon-

Periodic

Non-

Periodic

eg. cat.wav


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Acoustic ManipulationAcoustic Manipulation -- MATLabMATLab Recognizes wave files (.WAV)

load, play, write

Vast array of signal processing tools

Built-in functions

Ease of debugging

GUI-capable


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Pitch/Duration/Amplitude AlterationPitch/Duration/Amplitude Alteration

Pitch vowels only

As pitch increases, pitch period shrinks As pitch decreases, pitch period expands

Need to alter length between pitch marks

in order to alter pitch of speech signal


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Altering PitchAltering Pitch

X

Hanning

window

=

Original diphone Extracted

pitch period

Hanned

pitch periodC_A


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PSOLA Pitch Synchronous Overlap and Add

=

Altering Pitch ContdAltering Pitch Contd

50% Overlap + Add

Pitch Up > 50%

Pitch Down < 50%


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Altering Pitch ContdAltering Pitch Contd

X

=

Kaiserwindow

-naturally spoken

vowels contain 12-18

pitch marks

X 12


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Altering DurationAltering Duration Increase number of PSOLA iterations

(overlaps) to increase duration

Decrease number of PSOLA iterations(overlaps) to decrease duration

Altering AmplitudeAltering Amplitude

Multiplying the signal by a constant

If constant > 1, amplitude increase

If constant < 1, amplitude decrease


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SummarySummary

TTS System

Text

Pre-processingProsody Concatenation

words

System modularized


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ProgressProgress Work Completed / Current Status

Text pre-processing and prosodic manipulation for amulti-syllable word

Diphone concatenation 200+ diphones in database

Fully functional GUI implemented

Work To Be Done Sentence level synthesis

Expand diphone database

Fine-tuning and enhancing

Prepare for Poster Fair

Write final report


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Questions?Questions?

Contact Information

Michael Beddaoui

Abdel-Aziz El-Solh

[email protected]

[email protected]


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