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影像偽裝術的最新發展

影像偽裝術的最新發展. Chair Professor Chin-Chen Chang Feng Chia University National Chung Cheng University National Tsing Hua University. Multimedia (Watermarking). Classifications: Visible watermarking Invisible watermarking Robust watermarking Semi-fragile watermarking Fragile watermarking.

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影像偽裝術的最新發展

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  1. 影像偽裝術的最新發展 Chair Professor Chin-Chen Chang Feng Chia University National Chung Cheng University National Tsing Hua University

  2. Multimedia (Watermarking) • Classifications: • Visible watermarking • Invisible watermarking • Robust watermarking • Semi-fragile watermarking • Fragile watermarking

  3. Multimedia (Watermarking) (Cont.) • Visible watermarking • Easy to embed • Clear to see watermark

  4. Multimedia (Watermarking) (Cont.) • Invisible watermarking • Requirements: • Good visual quality of watermarked image • Robustness Watermarking Original image Watermarked image Watermark

  5. Multimedia (Image authentication) • Requirements: • Detect the tampered area • Try to restore the tampered area • Solutions: • Hamming codes Tampered image Detected image Restored image Image

  6. Multimedia (Secret sharing) • Classification: • Meaningless shadows • Meaningful shadows • Meaningless shadows • Requirements: • Unexpected user can not see the secret image • Good visual quality of reconstructed secret image

  7. Multimedia (Secret sharing) (Cont.) Sharing Shadow size: 256  256 Image size: 512  512 Reconstructing (2,4)-threshold secret sharing scheme PSNR=24 dB

  8. Multimedia (Secret sharing) (Cont.) • Meaningful shadows • Requirements: • Good visual quality of stego image • Secret image extraction and reconstruction • Solutions: • Applying steganography techniques • Applying image authentication mechanisms

  9. Multimedia (Secret sharing) (Cont.) Reconstructing Hiding Stego-image Reconstructed secret image Secret image Stego-image (n,2)-threshold secret sharing scheme Stego-image

  10. Multimedia (Visual cryptography) • Requirements: • Secret message delivery • Unexpected user can not see the message from an individual share • Solutions: • Using shadow patterns • Using meaningful shadow images • Using Circle Shares

  11. Multimedia (Visual cryptography) (Cont.) Staking Shadow 1 Shadow 2 Secret

  12. Multimedia (Visual cryptography) (Cont.) Staking Shadow 1 Shadow 2 Secret

  13. Multimedia (Visual cryptography) (Cont.) Rotating 40o Staking Staking Share 2 Share 1 Secret 1 “VISUAL” Secret 2 “SECRET”

  14. Multimedia (Steganography) • Classification: • The target of modification • Frequency domain (e.g. DCT, DWT, DFT) • Spatial domain (e.g. pixel values) • Compression domain (e.g. VQ, LAC, SOC) • Stego image restoration • Irreversible data hiding • Reversible data hiding

  15. Multimedia (Steganography) (Cont.) • Irreversible data hiding • Requirements: • High capacity • Good visual quality of stego images • Solutions: • Using Sudoku • Using wet paper codes concept • Using Hamming codes

  16. Multimedia (Steganography) (Cont.) • Reversible • Requirements: • Fully reconstructing cover image • Good visual quality of stego image • High capacity • Solutions: • Data hiding in VQ indices • Data hiding in LAC codes • Data hiding in SOC codes • …

  17. Data Hiding Hiding system Stego image Cover image 1 0 1 0 1 0 0 1 0 1 1 1 1 0 0 Secret message

  18. Cover Carriers • Image • Video • Sound • Text

  19. VQ Encoding (120,155,…,80) 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 (90,135,…,120) (100,125,…,150) … Index table Original Image (49,117,…,25) (50,42,…,98) (20,65,…,110) Codebook

  20. Previous Work of Steganography on VQ To find the closest pairs

  21. d(CW0, CW8) > TH d(CW13, CW14) > TH ,CW2 CW4, CW5 CW6, CW7 CW0, CW8, CW13, CW14 ,CW3 CW15, CW10 CW12, CW9 Unused CW1 1 CW11 0

  22. CW0, CW8, CW13, CW14 Index Table Unused Encode Index Table Original Image

  23. A secret message: 1 0 1 0 1 0 0 1 0 1 1 1 1 0 0 1 0 0 1 1 0 0 1 1 1 0 1 1 0 0 Index Table Secret bits CW1, CW2, CW4, CW5 CW6, CW7 CW11, CW3 CW15, CW10 CW12, CW9 1 0

  24. A secret message: 1 0 1 0 1 0 0 1 0 1 1 1 1 0 0 1 0 0 1 1 0 0 1 1 1 0 1 1 0 0 Index Table Secret bits CW1, CW2, CW4, CW5 CW6, CW7 CW11, CW3 CW15, CW10 CW12, CW9 1 0

  25. A secret message: 1 0 1 0 1 0 0 1 0 1 1 1 1 0 0 1 0 0 1 1 0 0 1 1 1 0 1 1 0 0 Index Table Secret bits

  26. Zhang and Wang’s Method(Embedding) Secret data:1000 1011… p2 255 0 1 2 3 4 0 1 2 3 4 0 1 10002 1 35 : : : : : : : : : : : : : … 11 2 3 4 0 1 2 3 4 0 1 2 3 2 … 10 0 1 2 3 4 0 1 2 3 4 0 1 0 Cover image … 9 3 4 0 1 2 3 4 0 1 2 3 4 3 … 8 1 2 3 4 0 1 2 3 4 0 1 2 1 … 7 4 0 1 2 3 4 0 1 2 3 4 0 4 … 6 2 3 4 0 1 2 3 4 0 1 2 3 2 … 5 0 1 2 3 4 0 1 2 3 4 0 1 0 … 4 3 4 0 1 2 3 4 0 1 2 3 4 3 … 3 1 2 3 4 0 1 2 3 4 0 1 2 1 … 2 4 0 1 2 3 4 0 1 2 3 4 0 4 … 1 2 3 4 0 1 2 3 4 0 1 2 3 2 … 0 0 1 2 3 4 0 1 2 3 4 0 1 0 Stego image p1 0 1 2 3 4 5 6 7 8 9 10 11 … 255 Magic Matrix

  27. Zhang and Wang’s Method (Extracting) p2 255 0 1 2 3 4 0 1 2 3 4 0 1 : : : : : : : : : : : : : … 11 2 3 4 0 1 2 3 4 0 1 2 3 2 … 10 0 1 2 3 4 0 1 2 3 4 0 1 0 … 9 3 4 0 1 2 3 4 0 1 2 3 4 3 … 8 1 2 3 4 0 1 2 3 4 0 1 2 1 Stego image … 7 4 0 1 2 3 4 0 1 2 3 4 0 4 … 6 2 3 4 0 1 2 3 4 0 1 2 3 2 … 5 0 1 2 3 4 0 1 2 3 4 0 1 0 … 4 3 4 0 1 2 3 4 0 1 2 3 4 3 … 3 1 2 3 4 0 1 2 3 4 0 1 2 1 … 2 4 0 1 2 3 4 0 1 2 3 4 0 4 … 135 1 2 3 4 0 1 2 3 4 0 1 2 3 2 … 0 0 1 2 3 4 0 1 2 3 4 0 1 0 p1 0 1 2 3 4 5 6 7 8 9 10 11 … 255 Magic Matrix Extracted secret data: 10002

  28. Sudoku • A logic-based number placement puzzle

  29. Sudoku (Cont.) • A Sudoku grid contains nine 3 × 3 matrices, each contains different digits from 1 to 9. • Each row and each column of a Sudoku grid also contain different digits from 1 to 9. • Property Possible solutions: 6,670,903,752,021,072,936,960 (i.e. ≈ 6.671×1021)

  30. Data Hiding Using Sudoku - 1 Reference Matrix M

  31. Data Hiding Using Sudoku (Embedding) (Cont.) Secret data:011 001 10… 279 Cover Image min. d( , ) = ((8-8)2+(4-7)2)1/2=3 d( , ) = ((9-8)2+(7-7)2)1/2=1 d( , ) = ((6-8)2+(8-7)2)1/2=2.24 Stego Image

  32. Data Hiding Using Sudoku (Embedding) (Cont.) Secret data:011 001 10… 279 Cover Image d( , ) = ((11-11)2+(15-12)2)1/2=3 d( , ) = ((15-11)2+(12-12)2)1/2=4 d( , ) = ((9-11)2+(14-12)2)1/2=2.83 min. Stego Image

  33. Data Hiding Using Sudoku (Extracting) (Cont.) Stego Image Extracted data: 279 = 011 0012

  34. Experimental Results

  35. Experimental Results (Cont.) The results of visual quality and Embedding capacity comparisons

  36. (7, 4) Hamming Coding • Encoding p1p2d1p3d2d3d4 d1d2d3d4 Encoding Data: 1 1 0 12 d2 d3  d4 = p3 1  0  1 = 0 d1 d3  d4 = p2 1  0  1 = 0 d1 d2  d4 = p1 1  1  1 = 1 10 1 0 1 0 1 p1p2d1p3d2d3d4 Encoded data

  37. (7, 4) Hamming Coding (Cont.) Error bit • Error Detection Received data: 1 0 1 0 1 1 1 Correcting Corrected data: 1 0 1 0 1 0 1 Error Position Parity check matrix H

  38. Matrix Coding Method • Embedding Cover Image (1010100)T = (1 1 1)T Stego Image  0 0 1 Secret data: 1 1 0 0… Parity check matrix H

  39. Matrix Coding Method (Cont.) • Extracting Stego Image (0010100)T = (1 1 0)T Extracted secret data: 1 1 0 0… ■ 7 pixels embed 3 bits

  40. “Hamming+1” Method • Embedding Cover Image 00001010 (1+1+0+1+1+0+0+1) mod 2= 1 or (0+1+0+1+1+0+0+1) mod 2= 0 00001100 (1010100)T = (1 1 1)T ? = Stego Image  0 0 1 Secret data: 1 1 0 0… Parity check matrix H

  41. “Hamming+1” Method (Cont.) • Extracting Stego Image (0+1+0+1+1+0+0+1) mod 2= 0 (0010100)T = (1 1 0)T = Extracted secret data: 1 1 0 0… ■ 8 pixels embed 4 bits

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