張真誠 逢甲大學 講座教授 中正大學 榮譽教授 清華大學 合聘教授 影像偽裝術的最新發展 張真誠 逢甲大學 講座教授 中正大學 榮譽教授 清華大學 合聘教授
Watermarking Image authentication Secret sharing Visual cryptography Steganography
Watermarking Visible watermarking Easy to embed Clear to see watermark
Watermarking (Cont.) Invisible watermarking Requirements: Good visual quality of watermarked image Robustness Watermarking Original image Watermarked image Watermark
Image authentication Requirements: Detect the tampered area Try to restore the tampered area Image Tampered image Detected image Restored image
Secret sharing Classification: Meaningless shadows Meaningful shadows
Secret sharing (Cont.) Sharing Shadow size: 256 256 Reconstructing Image size: 512 512 Reconstructing (2,4)-threshold secret sharing scheme PSNR=24 dB
Secret sharing (Cont.) Reconstructing Secret image Hiding Stego-image Reconstructed secret image Secret image Stego-image (2, n)-threshold secret sharing scheme Stego-image
Visual cryptography Stacking Shadow 1 Shadow 2 Secret
Visual cryptography (Cont.) Stacking Shadow 1 Shadow 2 Secret
Visual cryptography (Cont.) Rotating 40o Stacking Stacking Share 1 Share 2 Secret 1 “VISUAL” Secret 2 “SECRET”
Steganography The targets Restoration Frequency domain (e.g. DCT, DWT, DFT) Spatial domain (e.g. pixel values) Compression domain (e.g. VQ) Text Restoration Irreversible Reversible
Steganography (Cont.) Image Hiding system Stego image Cover image Secret message Stego image 1 0 1 0 1 0 0 1 0 1 1 1 1 0 0
Steganography (Cont.) Text Video Sound 壞的毛病 壞毛病 山東的蘋果 山東蘋果 我的媽媽 我媽媽 壞的毛病 壞毛病 山東的蘋果 山東蘋果 我的媽媽 我媽媽 主要的問題 主要問題 另外的一件事 另外一件事 其他的問題 其他問題 北京的大學 北京大學 Video Sound
Zhang and Wang’s Method (Embedding) 8 7 9 4 79 54 55 11 20 21 12 24 10 Secret data: 1000 1011… p2 255 1 2 3 4 1 2 3 4 1 : : : : : : : : : : : : : 10002 1 35 … 11 2 3 4 1 2 3 4 1 2 3 2 … 10 1 2 3 4 1 2 3 4 1 Cover image … 9 3 4 1 2 3 4 1 2 3 4 3 … 8 1 2 3 4 1 2 3 4 1 2 1 … 7 4 1 2 3 4 1 2 3 4 4 … 6 2 3 4 1 2 3 4 1 2 3 2 … 5 1 2 3 4 1 2 3 4 1 7 10 4 … 4 3 4 1 2 3 4 1 2 3 4 3 … 3 1 2 3 4 1 2 3 4 1 2 1 … 2 4 1 2 3 4 1 2 3 4 4 … 1 2 3 4 1 2 3 4 1 2 3 2 … 1 2 3 4 1 2 3 4 1 Stego image 1 2 3 4 5 6 7 8 9 10 11 … 255 p1 Magic Matrix
Zhang and Wang’s Method (Extracting) p2 7 10 4 255 1 2 3 4 1 2 3 4 1 : : : : : : : : : : : : : … 11 2 3 4 1 2 3 4 1 2 3 2 … 10 1 2 3 4 1 2 3 4 1 … 9 3 4 1 2 3 4 1 2 3 4 3 … 8 1 2 3 4 1 2 3 4 1 2 1 Stego image … 7 4 1 2 3 4 1 2 3 4 4 … 6 2 3 4 1 2 3 4 1 2 3 2 … 5 1 2 3 4 1 2 3 4 1 … 4 3 4 1 2 3 4 1 2 3 4 3 … 3 1 2 3 4 1 2 3 4 1 2 1 … 2 4 1 2 3 4 1 2 3 4 4 1 35 … 1 2 3 4 1 2 3 4 1 2 3 2 … 1 2 3 4 1 2 3 4 1 p1 1 2 3 4 5 6 7 8 9 10 11 … 255 Extracted secret data: 10002 Magic Matrix
Sudoku A logic-based number placement puzzle
Sudoku (Cont.) Property 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. Possible solutions: 6,670,903,752,021,072,936,960 (i.e. ≈ 6.671×1021)
Data Hiding Using Sudoku - 1 Reference Matrix M
Data Hiding Using Sudoku (Embedding) (Cont.) 8 7 11 12 79 54 55 20 21 24 10 9 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 9 7 Stego Image
Data Hiding Using Sudoku (Embedding) (Cont.) 8 7 11 12 79 54 55 20 21 24 10 9 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. 9 7 14 Stego Image
Data Hiding Using Sudoku (Extracting) (Cont.) 9 7 14 Stego Image Extracted data: 279 = 011 0012
Experimental Results
Experimental Results (Cont.) The results of visual quality and Embedding capacity comparisons Images Proposed PSNR C Baboon Barbara Boats Goldhill Jet(F16) Lena Pepper Sailboat Tiffany 44.68 44.77 44.94 44.84 45.02 44.97 44.67 1.5 Average 44.88