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A Study of Digital Image Coding and Retrieving Techniques

A Study of Digital Image Coding and Retrieving Techniques. 數位影像編碼與擷取技術之研究. 指導教授 : 張真誠 教授 研究生 : 周永振 Dept. of Computer Science and Information Engineering, National Chung Cheng University. Outline. Part 1: Compression domain data hiding Part 2: Data hiding using Sudoku

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A Study of Digital Image Coding and Retrieving Techniques

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  1. A Study of Digital Image Coding and Retrieving Techniques 數位影像編碼與擷取技術之研究 指導教授: 張真誠 教授 研究生: 周永振 Dept. of Computer Science and Information Engineering, National Chung Cheng University

  2. Outline • Part 1: Compression domain data hiding • Part 2: Data hiding using Sudoku • Part 3: Reversible data hiding for color image • Part 4: High payload data embedding for color image • Part 5: SOC improvement Yung-Chen Chou

  3. Introduction • Steganography • Secret data delivery • Visual quality vs. embedding capacity • Categories: • Compression domain • Spatial domain • Frequency domain • Grayscale image/color image • SOC improvement • Indicator • Eliminate the indicator Yung-Chen Chou

  4. Information hiding (Data hiding) Introduction (Cont.) Hiding system Stego image Cover image 1 0 1 0 1 0 0 1 0 1 1 1 1 0 0 Secret message Yung-Chen Chou

  5. VQ domain data hiding • Vector quantization Yung-Chen Chou

  6. d16 d12 d15 d14 d13 VQ domain data hiding (Cont.) • Codeword pairing {d12, d13, d14, d15, d16, d23, d24, d25, d26 d34, d35, d36, d45, d46, d56} cw6 cw2 cw5 cw4 cw1 cw3 G0 G1 G-1 d36>TH Yung-Chen Chou

  7. Indicator = ‘0’ Indicator = ‘1’ Encoded by cwi VQ domain data hiding (Cont.) • Data embedding NBVX = {x0, x1, x3, x4, X, X, X, x8, X, X, X, x12, X, X, X} Image If SMD(cwi,NBVX) <SMD(cwj, NBVX) then X is replaceable Else X is non-replaceable If secret bit = ‘0’ then encode X by cwi else encode X by cwj cwi cwj Yung-Chen Chou G0 G1

  8. VQ domain data hiding (Cont.) • Data extracting and restoring If SMD(cwi) < SMD(cwj) and indicator = ‘0’  restore X by cwi If SMD(cwi) < SMD(cwj) and indicator = ‘1’  restore X by cwj If SMD(cwi)  SMD(cwj) and indicator = ‘0’  restore X by cwj If SMD(cwi)  SMD(cwj) and indicator = ‘1’  restore X by cwi Image If X encoded by cwithen secret bit = ‘0’ If X encoded by cwjthen secret bit = ‘1’ cwi cwj Yung-Chen Chou G0 G1

  9. VQ domain data hiding (Cont.) • Experimental results Yung-Chen Chou

  10. VQ domain data hiding (Cont.) • Experimental results Yung-Chen Chou

  11. Data hiding using Sudoku • Spatial domain data embedding • Sudoku • A logic-based number placement puzzle Yung-Chen Chou

  12. Data hiding using 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) Yung-Chen Chou

  13. Data hiding using Sudoku (Cont.) Review Zhang and Wang’s method(Embedding) Extracting function: 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 … 2 7 4 0 1 2 3 4 0 1 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 2 3 4 3 1 … 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 Yung-Chen Chou

  14. 135 Extracted secret data: 10002 Data hiding using Sudoku (Cont.) Review 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 … 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 Yung-Chen Chou

  15. Data hiding using Sudoku (Cont.) - 1 Reference Matrix M Yung-Chen Chou

  16. 279 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 9 7 Stego Image Data hiding using Sudoku (Embedding) (Cont.) Secret data:011 001 10… Cover Image Yung-Chen Chou

  17. 279 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. 9 7 9 14 Stego Image Data hiding using Sudoku (Embedding) (Cont.) Secret data:011 001 10… Cover Image Yung-Chen Chou

  18. Data hiding using Sudoku (Extracting) (Cont.) Stego Image Extracted data: 279 = 011 0012 Yung-Chen Chou

  19. Experimental results Yung-Chen Chou

  20. Experimental results (Cont.) Yung-Chen Chou

  21. Data hiding for color images • True color and color palette image • Color pixel (Red, Green, Blue) • Reversibility Yung-Chen Chou

  22. Stego Data hiding for color images (Cont.) • Review Fridrich’s method R+G+B mod 2 = (115 + 216 + 112) mod 2 = 1 R+G+B mod 2 = (105 + 146 + 193) mod 2 = 0 Image Secret: 010… Yung-Chen Chou

  23. ( R, G, B) pi = (112, 217, 110) pi+1=(115, 216, 112) (115, 216, 112) (115, 112, 216) (216, 115, 112) (216, 112, 115) (112, 115, 216) (112, 216, 115) d0 = 3.74 d1 = 149.23 d2 = 145.68 d3 = 147.87 d4 = 147.11 d5 = 5.1 Sorting 00 01 10 11 d0 < d5 < d4 < d3 < d2 < d1 log2NG = log26 = 2 Data hiding for color images (Cont.) • Proposed method (Embedding) If d0 is first one then embeddable Else non-embeddable Image If d(pi+1, p’i+1) < TH=50 then embed secret Else non-embeddable require extra information Secret: 011… Stego Yung-Chen Chou

  24. ( R, G, B) (112, 217, 110) (112, 216, 115) (112, 216, 115) (112, 115, 216) (216, 112, 115) (216, 115, 112) (115, 112, 216) (115, 216, 112) d0 = 5.1 d1 = 147.11 d2 = 147.87 d3 = 145.68 d4 = 149.23 d5 = 3.74 Sorting 00 01 10 11 d5 < d0 < d3 < d1 < d2 < d4 log2NG = log26 = 2 Extracted data: 01 Data hiding for color images (Cont.) • Proposed method (Extracting and restoring) Stego Restored image Yung-Chen Chou

  25. Data hiding for color images (Cont.) • Experimental results Yung-Chen Chou

  26. Data hiding for color images (Cont.) • Experimental results Yung-Chen Chou

  27. c1 >c2, if (v1>v2) or (v1=v2 and r1>r2) or (v1 = v2 and r1=r2 and g1>g2) c1 = c2, if (r1=r2 and g1=g2 and g1=g2) c1 < c2, otherwise 0 1 0 1 0 c1 c2 c3 c4 c High payload data hiding for color images • Review Tzeng’s method v = 0.3 r + 0.59 g + 0.11 b v1 = 0.3 10+0.59 20+0.11 15 = 16.45 v2 = 8.17 v3 = 10.22 v4 = 15.21 vc = 18.17 Image Secret: 101… Yung-Chen Chou

  28. … 8 6 8 15 6 15 14 16 … 6 8 15 14 16 14+1=15 15 20 16 20 10 10 10+6 =16 Stego High payload data hiding for color images (Cont.) • The proposed (Embedding)  log2(8-6)=1 Image  log2(20-10)=3 Secret: 11010010100… Yung-Chen Chou

  29. 8 15 6 … 16 20 10 6 8 15 14 16 14-15=1=12  log2(20-10)=3 16-10 = 6 = 1102 1 110 Stego High payload data hiding for color images (Cont.) • The proposed (Extracting)  log2(8-6)=1 Extracted secret: Yung-Chen Chou

  30. High payload data hiding for color images (Cont.) • Experimental results Yung-Chen Chou

  31. High payload data hiding for color images (Cont.) Yung-Chen Chou

  32. 0 0 52 52 1 1 53 53 2 2 49 49 3 3 50 50 4 4 57 57 5 5 55 55 6 6 48 48 7 7 47 47 State codebook Index table State codebook SOC improvement • Scan-order coding (SOC) Indicator Compression code: …1 011… Index table Indicator Compression code: …0 01100010… Yung-Chen Chou

  33. α Secret = 0 If SMD(α, NBVB) <SMD(α, NBVB) Secret = 1 α Secret = 0 000 ||α If SMD(α, NBVB) SMD(α, NBVB) 111 || α Secret = 1 SOC improvement (Cont.) • Review Lin and Chang’s method NBVB = {b0, b1, b3, b4, X, X, X, b8, X, X, X, b12, X, X, X} Yung-Chen Chou

  34. Can be compressed by SOC (i.e. indicator = 1) Sorted SCB Index table For indicator = 1 Sorted SCB For indicator = 0 SOC improvement (Cont.) • The proposed method (Encoding) Index table If SMD(cw50, NBVBi) < SMD(cw55, NBVBi) Compression code: …101 Else Compression code: … 111 010 Yung-Chen Chou

  35. Index table For indicator = 1 For indicator = 0 For indicator = 1 Sorted SCB For indicator = 0 SOC improvement (Cont.) Can be compressed by SOC (i.e. indicator = 1) Index table If SMD(cw130, NBVBi) < SMD(cw3, NBVBi) Compression code: … 10000010 Else Compression code: … 11111111 10000010 Yung-Chen Chou

  36. Using cw50 to decode Bi For indicator = 1 Sorted SCB For indicator = 0 SOC improvement (Cont.) • The proposed method (Decoding) Compression code: …101… The indicator for next block is ‘1’ SMD(cw55, NBVBi) SMD(cw50, NBVBi) Index table Yung-Chen Chou

  37. Using cw50 to decode Bi For indicator = 1 Sorted SCB For indicator = 0 SOC improvement (Cont.) Compression code: …111 010… The indicator for next block is ‘1’ Index table Yung-Chen Chou

  38. SOC improvement (Cont.) Yung-Chen Chou

  39. SOC improvement (Cont.) • Experimental results

  40. Conclusions • Steganography • Achieve high payload data embedding • Reversibility • Achieve high payload data embedding for color images • Success eliminate the indicator of SOC Yung-Chen Chou

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