A Tutorial on Hidden Markov Models and Selected Applications in Speech Recognition

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A Tutorial on Hidden Markov Models and Selected Applications in Speech Recognition LAWRENCE R. RABINER, FELLOW, IEEE Presented by: Chi-Chun Hsia. Markov Chain. Markov Chain. Markov Chain. It results in a Geometric Distribution. And then, what does “hidden” means?. - PowerPoint PPT Presentation

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2004/11/16 1

A Tutorial on Hidden Markov Models and Selected Applications in Speech Recognition

LAWRENCE R. RABINER, FELLOW, IEEEPresented by: Chi-Chun Hsia

2004/11/16 2

Markov ChainMarkov Chain

2004/11/16 3

Markov ChainMarkov Chain

2004/11/16 4

Markov ChainMarkov Chain

And then, what does “hidden” means?

It results in a Geometric Distribution

2004/11/16 5

Extension to Hidden Markov ModelExtension to Hidden Markov Model

2004/11/16 6

Extension to Hidden Markov ModelExtension to Hidden Markov Model

2004/11/16 7

Elements of an HMMElements of an HMM

2004/11/16 8

The Three Basic ProblemsThe Three Basic Problems

2004/11/16 9

Solution to Problem 1Solution to Problem 1

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Solution to Problem 1Solution to Problem 1

2004/11/16 11

Forward-Backward ProcedureForward-Backward Procedure

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Forward-Backward ProcedureForward-Backward Procedure

2004/11/16 13

Forward-Backward ProcedureForward-Backward Procedure

2004/11/16 14

Forward-Backward ProcedureForward-Backward Procedure

2004/11/16 15

Solution to Problem 2Solution to Problem 2

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Solution to Problem 2Solution to Problem 2

2004/11/16 17

Viterbi AlgorithmViterbi Algorithm

2004/11/16 18

Viterbi AlgorithmViterbi Algorithm

2004/11/16 19

Solution to Problem 3Solution to Problem 3

2004/11/16 20

Solution to Problem 3Solution to Problem 3

2004/11/16 21

EM Algorithm for HMMEM Algorithm for HMM

X.D. HUANG, Y. ARIKI, M.A. JACK

HIDDEN MARKOV MODELSFOR SPEECH RECOGNITION

EDINBURGH UNIVERSITY PRESS

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Types of HMMsTypes of HMMs

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Continuous Type HMMsContinuous Type HMMs

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Autoregressive HMMsAutoregressive HMMs

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Optimization CriterionOptimization CriterionMaximum Likelihood (ML)

Maximum Mutual Information (MMI)

Minimum Discrimination Information (MDI)

Minimum Classification Error (MCE) Chang.

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Implementation Issues for HMMsImplementation Issues for HMMs

• Scaling

• Multiple Observation Sequences

• Initial Estimates of HMM Parameters

• Effect of Insufficient Training Data

• Choice of Model

2004/11/16 27

ScalingScaling

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ScalingScaling

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ScalingScaling

And so on and on and on and on……………..

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Multiple Observation SequencesMultiple Observation Sequences

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Initial Estimates of HMM ParametersInitial Estimates of HMM Parameters

2004/11/16 32

Effect of Insufficient Training DataEffect of Insufficient Training Data

2004/11/16 33

Choice of ModelChoice of Model