1. Increasing Watermarking Robustness using Turbo Codes
Corina Nafornita, Alexandru Isar, Maria Kovaci
Politehnica University of Timisoara
{corina.nafornita, alexandru.isar,
WISP 2009, Budapest, Hungary

2. Goal Duo-binary turbo codes Robustness Capacity Imperceptibility
Watermarking requirements
Perceptual mask - DWT
WISP 2009, Budapest, Hungary

3. Barni et al., 2001 Daubechies-6 Watermark Marked Original Mask IDWT
WISP 2009, Budapest, Hungary

4. Proposed solution Artifacts  low resolution mask
High resolution mask
Watermark easily erased
All resolution levels
New approach: duo-binary turbo codes
WISP 2009, Budapest, Hungary

5. New method Bior2.2 DBTC Encoded Watermark Marked Original New mask
message
New mask
Encoded Watermark
Original
Marked
DWT
IDWT
Bior2.2
Select only higher coefficients!!!
WISP 2009, Budapest, Hungary

6. Mask estimation Low resolution vs. High resolution
(Barni et al.,2001) (Nafornita et al.,2006)
WISP 2009, Budapest, Hungary

7. Duo-Binary Turbo Code 8-state duo binary RSC encoder , rate 2/3.
RSC r-ary
ilv
Input sequence r u 1 c1 c2 u2 1
c =u0 S1 u1 S3 S2
8-state duo binary RSC encoder , rate 2/3.
Encoder polynomials: 15 (feedback) and 13 (redundancy)
WISP 2009, Budapest, Hungary

8. Experiments Test image Lena Message length: 768 bits Block size 7
Threshold 10
Watermark strength =9
PSNR obtained dB
Lena
Watermarked Lena
WISP 2009, Budapest, Hungary

9. AWGN: σ=3.25…15
BER vs. 
BER vs. PSNR
WISP 2009, Budapest, Hungary

10. JPEG compression: Q=10…100 BER vs. quality factor BER vs. PSNR
WISP 2009, Budapest, Hungary

11. Coded vs. Uncoded Attack vs. BER BER Uncoded DBTC
JPEG compression, Q=50,
PSNR=32.94 dB
AWGN, =8,
PSNR=29.29 dB
0.0885
3.25·10-4
WISP 2009, Budapest, Hungary

12. Conclusions BER decreases in both cases when using turbo codes
Less severe attacks:
perfect reconstruction,
the attack modeled like an AWGN channel with high SNR.
Coding gain of DBTC higher than 2 dB
WISP 2009, Budapest, Hungary