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A Digital Watermarking Scheme Based on Singular Value Decomposition. Speaker: Prof. Chin-Chen Chang. Outline. Digital Watermarking System Watermarking Category SVD (Singular Value Decomposition) Proposed Scheme Experimental Results Conclusions. Digital Watermarking System.
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A Digital Watermarking Scheme Based on Singular Value Decomposition Speaker: Prof. Chin-Chen Chang
Outline • Digital Watermarking System • Watermarking Category • SVD (Singular Value Decomposition) • Proposed Scheme • Experimental Results • Conclusions
Watermarking Category- Robustness • Three categories • Robust watermarking schemes • Fragile watermarking schemes • Semi-fragile watermarking schemes
Watermarking Category- embedding approach • Spatial domain-based scheme • Low computational complexity • Lower robustness • Frequency domain-based scheme • Need more computation • Provide better robustness
• SVD-based schemes • Similar to frequency domain based scheme • SVD can be considered as a transformation
SVD • Singular Value Decomposition • Assume that rank of A is r. • U and V are N x N orthogonal matrices, U x UT=I, V x VT=I • S is an N x N diagonal matrix, σ1 ≥σ2 ≥…≥σr ≥σr+1 =…=σN =0
Proposed Scheme (1/3) 4 1 0 0 1 1 0 0 1 1 0 1 0 1 1 0 0 0 1 0 1 1 0 1 0 4 Binary watermarking image One bit needs to be embedded in three different blocks Original image Use a one way hash function based on Rabin’s scheme to decide the embedding block
3.2527 3.2527+δxWi Proposed Scheme (2/3) • Embedding process Wi = 1, δ = 20 SVD 23.2527 U x x VT
The same process 18.6047-5.4539 =13.1508 > 10 W’1=1 W’1+W’2+W’3 > 2 W’2=0 W’=1 W’2=1 Proposed Scheme (3/3) • Extracting process δ/2 = 10 SVD U x x VT
Experimental Results (1/7) • Seven 512x512 gray-scale test images and one 64x64 binary image
Two measurements • PSNR • Peak Signal-to-Noise Ratio • BCR • Bit Correction Ratio
Original image Watermarked image (PSNR = 35.37dB) Extracted watermark Bit Correction Ratio = 100%
Watermarked image after JPEG compressing (PSNR = 35.87dB) Extracted watermark (Bit Correction Ratio = 87.92%)
Watermarked image after sharpening process (PSNR = 29.23dB) Extracted watermark (Bit Correction Ratio = 95.73%)
Watermarked image after blurring process (PSNR = 35.60dB) Extracted watermark (Bit Correction Ratio = 92.41%)
Watermarked image after cropping process (PSNR = 35.60dB) Extracted watermark (Bit Correction Ratio = 90.19%)
Watermarked image after adding noise (PSNR = 32.54dB) Extracted watermark (Bit Correction Ratio = 89.28%)
Conclusion • SVD-based watermarking scheme for binary logo • The proposed scheme has good efficiency • The PSNR values of the watermarked images are all greater than 31 dB