Содержание
- 2. Outline Reminder Linear signal decomposition Optimal linear transform: KLT, principal component analysis Discrete cosine transform Definition,
- 3. Reminder: Linear Signal Representation Representation
- 4. Motivations Fundamental question: what is the best basis? energy compaction: minimize a pre-defined error measure, say
- 5. KLT: Optimal Linear Transform Signal dependent Require stationary signals How do we communicate bases to the
- 6. Discrete Cosine Transforms Type I Type II Type III Type IV
- 7. DCT Type-II 8 x 8 block middle frequency horizontal edges vertical edges orthogonal real coefficients symmetry
- 8. DCT Symmetry
- 9. DCT: Recursive Property An M-point DCT–II can be implemented via an M/2-point DCT–II and an M/2-point
- 10. Fast DCT Implementation 13 multiplications and 29 additions per 8 input samples
- 11. Block DCT
- 12. Filtering LTI Operator
- 13. Down-Sampling 2 Linear Time-Variant Lossy Operator
- 14. Up-Sampling 2
- 15. Filter Bank First FB designed for speech coding, [Croisier-Esteban-Galand 1976] Orthogonal FIR filter bank, [Smith-Barnwell 1984],
- 16. FB Analysis Q 2 2 2 2
- 17. Perfect Reconstruction With Aliasing Cancellation Distortion Elimination becomes
- 18. Half-band Filter Standard design procedure Design a good low-pass half-band filter Factor into and Use the
- 19. Spectral Factorization Re Im Zeros of Half-band Filter Real-coefficient z and z* must stay together Orthogonality
- 20. Spectral Factorization: Orthogonal Re Im Re Im
- 21. Spectral Factorization: Symmetry Re Im 8 zeros Im Re Im Re
- 22. History: Wavelets Early wavelets: for geophysics, seismic, oil-prospecting applications, [Morlet-Grossman-Meyer 1980-1984] Compact-support wavelets with smoothness and
- 23. From Filter Bank to Wavelet [Daubechies 1988], [Mallat 1989] Constructed as iterated filter bank Discrete Wavelet
- 24. 1-Level 2D DWT input image LL: smooth approximation LH: horizontal edges HL: vertical edges HH: diagonal
- 25. 2-Level 2D DWT
- 26. 2D DWT
- 27. Time-Frequency Localization best time localization best frequency localization STFT uniform tiling wavelet dyadic tiling Heisenberg’s Uncertainty
- 28. Wavelet Packet Iterate adaptively according to the signal Arbitrary tiling of the time-frequency plain 0 frequency
- 29. Scaling and Wavelet Function Discrete Basis Continuous-time Basis product filters scaling function wavelet function
- 30. Convergence & Smoothness Not all FB yields nice product filters Two fundamental questions Will the infinite
- 31. Regularity & Vanishing Moments In an orthogonal filter bank, the scaling filter has K vanishing moments
- 32. Polyphase Representation Q x[n] 2 2 2 2
- 33. Lattice Structure x[n] 2 2 … Orthogonal Lattice Linear-Phase Lattice x[n] 2 2
- 34. FB Design from Lattice Structure Set of free parameters Modular construction, well-conditioned, nice built-in properties Complete
- 35. Lifting Scheme x[n] 2 2 … …
- 37. Скачать презентацию