Speech technology in telecommunications

Garant předmětu:

Přednášející:

Cvičící:

Předmět zajišťuje:

katedra teorie obvodů

Anotace:

The subject is devoted to basis of speech processing addressed to students of master program with special focus on communication applications as speech technology has currently many applications in communication systems. Further information can be found at http://noel.feld.cvut.cz/vyu/ae2m31rat . Detailed information for registered students can be found at teaching portal http://moodle.kme.feld.cvut.cz .

Požadavky:

Bases of digital signal processing are supposed as preliminary knowledge.

Osnova přednášek:

1. Introduction - speech signal, basic characteristics, speech production model

2. Digitalization and basic coding strategies (PCM, ADPCM, a-law)

3. Spectral characteristics of speech signal (DFT a LPC spectrum, LSF a LSP)

4. Vocoders used in telecommunications (RPE-LTP, CELP, ACELP)

5. Methods of noise suppression for speech signals (channel and acoustic noises, VAD)

6. Echo cancellation in speech signal

7. Measurement of speech quality (subjective and objective methods)

8. Principles of speech recognition: basic tasks, feature extraction, DTW algorithm

9. Small vocabulary recognizer based on HMM (HTK toolkit)

10. Speaker recognition: verification and identification.

11. Speech synthesis - basic principles (concatenative and formant synthesis, PSOLA)

12. Voice controlled dialogue communication systems

13. Packet loss concealment for speech transmitted via communication channel

14. Further application of speech processing in communication systems. Reserve

Osnova cvičení:

1. Introduction: speech signal, tools for analysis, sources of speech signals

2. Basic time-domain characteristics: energy, intensity, zero-crossing, fundamental frequency

3. Spectral characteristics: short-time DFT and LPC spectrum, spectrogram

4. LPC based vocoder: implementation of particular functional blacks

5. Suppression of additive noise in speech signal

6. Echo cancellation

7. Cepstrum and cepstral distance: voice activity detection, features for recognition

8. DTW based recognition: simple recognizer of particular words

9. HMM based recognition: basic tasks and demonstration of HMM modelling

10. Speaker verification based on GMM

11. Speech synthesis: implementation of formant synthesis, demonstration of available tools

12. Semester work presentations

13. Semester work presentations

14. Reserve. Credits

Cíle studia:

The goals of the subject is to introduce used speech technology in the most important communication applications. Students should manage the knowledge as basic characteristics of speech signal, speech coding, speech enhancement, speech recognition, speech synthesis, etc. Students will practice basic tasks of speech processing in MATLAB environment and also other publicly available tools for speech analysis will be used. As a homework, students will elaborate semester project which will be presented at the exercise according to planned schedule.

Studijní materiály:

[1] Rabiner, L., Schafer, R. W.: Introduction to Digital Speech Processing Foundations and Trends in Signal Processing). Now Publishers Inc, 2007.

[2] Huang, X., Acero, A., Hon, H.-W.: Spoken Language Processing. Prentice Hall, 2001.

[3] Deller Jr., J. R., Hansen, J. H. L., Proakis, J. G.: Discrete-time Processing of Speech Signals. Wiley, 2000.

[4] McLoughlin, I.: Applied Speech and audio Processing: With Matlab Examples. Cambridge University Press, 2009.

[5] Jelinek, F.: Statistical Methods for Speech Recognition (Language, Speech, and Communication). The MIT Press, 1998.

[6] ITU-T Recommendations - http://www.itu.int/ITU-T

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