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Hidden Digital Watermarks in Images

Hidden Digital Watermarks in Images. Chiou-Ting Hsu and Ja-Ling Wu, Senior Member, IEEE IEEE TRANSACTIONS ON IMAGE PROCESSING, VOL. 8, NO. 1, JANUARY 1999, pp. 58 -68 Adviser : Dr. Chang, Chin-Chen Reporter : Huang, Chang-Chin Date : 2003/04/22. Outline. INTRODUCTION

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Hidden Digital Watermarks in Images

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  1. Hidden Digital Watermarks in Images Chiou-Ting Hsu and Ja-Ling Wu, Senior Member, IEEE IEEE TRANSACTIONS ON IMAGE PROCESSING, VOL. 8, NO. 1, JANUARY 1999, pp. 58 -68 Adviser : Dr. Chang, Chin-Chen Reporter : Huang, Chang-Chin Date : 2003/04/22

  2. Outline • INTRODUCTION • EMBEDDING METHODS • WATERMARK EXTRACTING METHOD • EXPERIMENTAL RESULTS • CONCLUSION

  3. INTRODUCTION • resistant to lossy data compression, e.g., the Joint Photographic Experts Group (JPEG) compression; • resistant to image manipulation and processing operations, e.g., cut-and-paste, filtering, etc.

  4. EMBEDDING METHODS Ir C D E1 O1 F2 E2 A B GO TO WATERMARK EXTRACTING F1 Wr

  5. EMBEDDING METHODS (A)Pseudorandom Permutation of the Watermark • First：number each pixel from zero to (M1 * M2). • Second：generate each number in random order. • Finally：generate the coordinate pairs by mapping the random sequence number into a 2-D sequence. Return Embedding

  6. EMBEDDING METHODS (B)Block-Based Image-Dependent Permutation of the Watermark block (i,j) is shuffled to block (k,l) by the block-based permutation Wp Wb Wp Wb Return Embedding

  7. EMBEDDING METHODS (C)Block Transformation of the Image Y=FDCT(X) [forward DCT] 1. RGBYCbCr Y = 0.2990R + 0.5870G + 0.1140B Cb =-0.1687R - 0.3313G + 0.5000B Cr = 0.5000R - 0.4187G - 0.0813B 2. DCT Transfer Return Embedding

  8. EMBEDDING METHODS (D)Choice of Middle-Frequency Coefficients Return Embedding

  9. EMBEDDING METHODS (E1)Modification of the DCT Coefficients • binary polarity pattern • reverse the corresponding polarity Return Embedding

  10. EMBEDDING METHODS (E2)Modification of the DCT Coefficients • Luminance quantization table • polarity Return Embedding

  11. EMBEDDING METHODS (F1)Inverse Block Transform map the modified middle-frequency coefficients into Y to get Return Embedding

  12. EMBEDDING METHODS (F2)Inverse Block Transform inverse DCT (IDCT) of the associatedresult to obtained the embedded image = IDCT( ) Return Embedding

  13. WATERMARK EXTRACTING METHOD Ir O1 Wr GO TO WATERMARK EMBEDDING

  14. EXPERIMENTAL RESULTS 1

  15. EXPERIMENTAL RESULTS 2

  16. EXPERIMENTAL RESULTS 3

  17. EXPERIMENTAL RESULTS 4

  18. CONCLUSION • image resampling and image rotation, are still challenging to our current work.

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