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Speech Recognition

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Introduction

What is Speech Recognition?

- Voice Recognition? Where can it be used?

- Dictation

- System control/navigation- Commercial/Industrial applications

- Hand held digital recorders

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Contents:

Continuous/Discrete

How does it work? Recent improvements

Current software options

Future of SR

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Continuous or Discrete? Continuous speech

- dictation

Discrete speech

- system controls

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How does SR work? Recognition

Training

Correction

Command/Control

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Recognition (1)Voice Input Analog to Digital Acoustic Model

Language Model

Display Speech EngineFeedback

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Recognition (2)

Acoustic Modeling

Spoken words: I think there are..

Phonemes: ay th-in-nk-kd dh-eh-r aa-r

H.M.M.s: 5 state representation

Speech Engine

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Recognition (3)

Language Modeling

Word context

Word frequency

Transition possibilities

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Voice Training (1)Can be done by:

Predetermined text segments

Individual words

Compare new acoustic with old and combines

More training = better recognition

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Voice Training (2)

User specific Voice file

Voice qualities

Pronunciation

Patterns of word use

Preferred vocabulary

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Making Corrections Move cursor by voice command

Memorize edit commands

List of possible alternatives

Make correction manually

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Command/Control Desktop grid

Program or Link name/number

URL name

Memorized commands

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RecentImprovements in SR

Faster training ~10 min.

Better recognition ~95%

More compatible software

Better system control/command

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Current Software Options for PC Dragon Systems Naturally Speaking

Philips FreeSpeech

IBM ViaVoice

Lernout & Hauspie Voice Xpress

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How well do the work?Training Dictation

Correct.

App.

Integrat.

Command

- Control

Dragon Excellent Excellent Good Good

Philips Fair Fair Good Good

IBM Excellent Good Good Excellent

L & H Good Good Good Good

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Future of SR SUI Speech-based UserInterface

Improvements needed:

- Greater accuracy

- Greater system control/command

- More compatible software

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Conclusion SR Uses

How does it work?

Current Software

Problems of SR

More SR coming soon.

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References 1. Alwang, Greg. Speech Recognition, PC Magazine, December 1

1999

2. Hauptmann, Alexander G. Jang, Photina Jaeyun. Carnegie Mellon

University. Learning to Recognize Speech by Watching Television,IEEE Intelligent Systems, September/October 1999.

3. Miastkowski, Stan. Latest Speech Software Gets You Up and

Running Faster, PC World, November 1999.