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Wavelet Transform and SPIHT Coding

Wavelet Transform and SPIHT Coding. Outline. Wavelet Transform SPIHT Coding Multiple Description Coding. Wavelet Transform. WHY Transform ? (1)energy compaction 能量集中在較少的區塊中 (2)decorrelation 去除相鄰點之間的相關性. Wavelet Transform. LL. HL. LH. HH. L. H. Discrete Wavelet Transformation.

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Wavelet Transform and SPIHT Coding

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  1. Wavelet Transform and SPIHT Coding

  2. Outline • Wavelet Transform • SPIHT Coding • Multiple Description Coding

  3. Wavelet Transform • WHY Transform ? (1)energy compaction 能量集中在較少的區塊中 (2)decorrelation 去除相鄰點之間的相關性

  4. Wavelet Transform

  5. LL HL LH HH L H Discrete Wavelet Transformation

  6. Discrete Wavelet Transformation 第一階 第二階 第三階

  7. 96.64% 0.41% 0.92% 0.94% 0.35% 0.43% 0.27% 5/3 Lena 2-level

  8. 使用LL2回復 PSNR=29.2137dB

  9. Data Extension

  10. Period or Symmetric Extension Lena

  11. SPIHT Coding DWT SPIHT IWT

  12. SPIHT Coding • Proposed by Said and Pearlman in 1996 • Regard tree as the unit • Idea of zerotree • A. Said and W. A. Pearlman, “A new, fast, and efficient image codec based on set partitioning in hierarchical trees, ” IEEE Trans. Circuits Syst. Video Technol., vol. 6, no. 3, pp. 243-250, June 1996.

  13. SPIHT Coding

  14. Two Type Zerotree TYPE A TYPE B

  15. SPIHT Coding Initial threshold = T T=T/2 LSP: List of Significant Pixel LIP: List of Insignificant Pixel LIS: List of Insignificant Set

  16. Compression Performance with Various Filters Lena

  17. SPIHT的錯誤回復 • 因封包遺失所造成的圖形品質降低 • 使用一些方法將遺失的部份回復

  18. Multiple Description Coding • 利用額外的資訊去達到錯誤保護的效果 • 先附加較重要的資料

  19. Multiple Description Coding

  20. Multiple Description Coding

  21. Multiple Description Coding Lena 0.125bpp 10% packet lost Unprotect PSNR=14.29dB MDC PSNR=27.95dB

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