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
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 F1 Wr 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 = R G B
Cb = R G B
Cr = R G B
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 associated result to obtained the embedded image
= IDCT( )
Return
Embedding

13. WATERMARK EXTRACTING METHODIr 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.