1. Speech Signal Processing I By Edmilson Morais And Prof. Greg. Dogil Second Lecture Stuttgart, October 25, 2001

2. The Speech Signal No-stacionary signal No-stacionary signal Voiced – almost periodic (Concept of pitch) Voiced – almost periodic (Concept of pitch) Unvoiced (aleatory) Unvoiced (aleatory) Transitions (Bursts,...) Transitions (Bursts,...) Range of the Pitch Range of the Pitch Male : Male : Female : Female :

3. Sampling Theory Low-pass filter SampleHold on Low-pass filter X(n) has to be limited in band The sampling frequency has to be higher or equal to 2 times the maximum frequency in x(n)

4. Linear Filters Finite impulse response filters

5. Matlab : Graphical visualization – Optimization in a hiperbolic (quadratic) surface Mean squared error - E Wei ght

6. SDSP : Looking through time time amplitude Speech signal : Analog and digital Sampling rate quantization

7. SDSP : Transformation and Digital filters Transformations Z-Transforms, Fourier transforms Digital filters FIR, IIR

8. SDSP – Frame based analysis Hanning window : w Waveform multiplied for the hanning window : xw Magnitude of the spectrum of xw Freq. Response of the LP-filter

9. SDSP - Looking at frequency components through time Current Previous Current Previous Before smoothing After smoothing

10. SDSP : Vector quantization Voronoi Space : Centroid and Distortion meassure

11. TTS - Waveform generation for TTS Analysis and Resynthesis – Coding and Decoding Analysis and Resynthesis – Coding and Decoding LP Analysis A(z) InverseFilter 1 A(z) PitchMarks Prototypes Sampling SynthesisFilter A( z ) TFIResidue Synthesis x e E n StorageEnviroment x A A A F o OriginalSpeechSignal SynthesizedSpeechSignal Coding Decoding Prosodic Information. Marks Marks F o E n U/UV U/UV.. Parametrization : Mapping the waveform into a set of parameters Reconstruction: Synthesis of the waveform from the set of parameters. Prosody : F0 F0 Duration Duration Amplitude Amplitude A – LP coeficients e – LP residue En – Prototypes Fo – Fundamental frequency U/UV – Voiced / Unvoiced transitions

12. TTS - Waveform generation for TTS Speech coding Speech coding Parametric coders, Waveform coders, Hybrid coders Parametric coders, Waveform coders, Hybrid coders TTS – Concatenative approach TTS – Concatenative approach Time scale and Frequency scale modifications Time scale and Frequency scale modifications Spectral smoothings Spectral smoothings Unit selection Unit selection OriginalResynthesized sin(x+  ) Modified : sin(x+  ) OriginalTTS

13. ASR - Automatic Speech Recognition Front-End Signal Processing Front-End Signal Processing Feature extraction Feature extraction Perceptual domain, Articulatory domain Perceptual domain, Articulatory domain Acoustic modeling Acoustic modeling HMM : Hidden Markov Model HMM : Hidden Markov Model ANN/HMM : Hybrid models - Artificial Neural Network and HMM ANN/HMM : Hybrid models - Artificial Neural Network and HMM Statistical Language Modeling Statistical Language Modeling N-grammars, smoothing techniques N-grammars, smoothing techniques Search : Decoding Search : Decoding Viterbi, Stack decoding,... Viterbi, Stack decoding,...

14. ASR – HMM - Topology Ergotic model Left-right model

15. ASR – HMM – Basic principle aaaaa a a aa a aa a

16. ASR – HMM - Viterbi alignment

17. ASR – HMM – Forward-Backward

18. ASR – ANN/HMM

19. Evaluation : Exercises and Simulations List of Exercises List of Exercises SDSP, TTS, ASR SDSP, TTS, ASR Simulations Simulations SDSP SDSP Vector quantization Vector quantization TTS TTS Waveform Interpolation Waveform Interpolation ASR ASR Acoustic modeling using : HMM and ANN+HMM Acoustic modeling using : HMM and ANN+HMM Language modeling Language modeling Decoding Decoding

20. Evaluation : Report Reports Reports Write the analysis and results of the simulation in a format of a paper Write the analysis and results of the simulation in a format of a paper 4 pages, two colunms. Sections Abstract Introduction Brief theoretical description of the method Methodology used to perform the experiment Results Conclusions and suggestions for further works Bibliograph

21. Days of classes Normal semester 2001 October : 18, 25, (01 is a hollyday) November : 8, 15, 22, 29 December : 6,13,20 2002 January : 10,17,24,31 February : 7,14 Total : 15 days. Option two 2001 October : 18, 25 November : 8, 15, 22, 29 2002 February : 7,14 March : An one week block seminar : 1.5 hours a day. Total : 13 days. Option one 2001 October : 16,18,23,25,30 November : 6,8,13,15,20,22,27,29 2002 February : 5,7,12,14 Total : 17 days. Option three 2002 March : An one week block seminar : 3 hours a day. Equivalent to 15 days