Post on 21-Dec-2015
Multimedia SecurityDigital Video Watermarking
Supervised by Prof. LYU, Rung Tsong Michael
Presented by Chan Pik Wah, Pat
Nov 20, 2002
Department of Computer Science and Engineering
The Chinese University of Hong Kong
Department of Computer Science and Engineering The Chinese University of Hong Kong
Outline
Motivation Research objective Background Literature Review New Video Watermarking Algorithm Future Direction Conclusion
Department of Computer Science and Engineering The Chinese University of Hong Kong
Why need Multimedia Security?
Easier to transfer multimedia documents across the Internet
Copyright protection of content Multimedia Security and Multimedia
Copyright Protection Encryption and control access Digital Watermarking
Motivation
Department of Computer Science and Engineering The Chinese University of Hong Kong
Cryptography ensures confidentiality, authenticity, and integrity
Cannot help after decryption Digital Watermarking can help
Prove ownership Identify a misappropriating person Trace the marked document’s
dissemination through the network
Why need Digital Watermark?
Motivation
Department of Computer Science and Engineering The Chinese University of Hong Kong
Different interesting watermarking approaches have been proposed
Most of Video Watermarking is based on the techniques of the image watermarking
Video watermarking introduces some issues not present in image watermarking
Frame averaging, frame dropping, frame swapping, statistical analysis, interpolation …
Why need Video Watermark?
Motivation
Department of Computer Science and Engineering The Chinese University of Hong Kong
Research objective Survey and investigation on multimedia
security issues and multimedia watermarking scheme.
Compared and evaluate various watermarking scheme
A new approaches and procedures for multimedia security based on watermarking are proposed.
Experiment will be done on this proposed approach
Objective
Department of Computer Science and Engineering The Chinese University of Hong Kong
Digital Watermarking
Watermarking is a concept of embedding a special pattern, watermark, is embedded into a document
Watermarking is a key process in the protection of copyright ownership of electronic data
Background
Department of Computer Science and Engineering The Chinese University of Hong Kong
Digital watermarking
Detection Algorithm
WatermarkOr
Confidence measureTest Image Ì
Watermark W and/or
original image I
Secret / public key K
Watermarking Algorithm
WatermarkedImage ÌStego-Image I
Watermark W
Secret / public key K
Background
Department of Computer Science and Engineering The Chinese University of Hong Kong
Properties of Watermark Invisibly Capacity (Number of bits can be hidden) Low error probability Robustness
Image watermarking ( filtering, resizing, contrast enhancement, cropping, rotation... )
Video watermarking ( frame averaging, frame dropping, frame swapping, statistical analysis, interpolation... )
Background
Department of Computer Science and Engineering The Chinese University of Hong Kong
Application of Watermarking Owner Identification Proof of Ownership Transaction Tracking Content Authentication Broadcast Monitoring Copy Control Device Control Automatic monitoring of copyrighted
material on the Web
Background
Department of Computer Science and Engineering The Chinese University of Hong Kong
Attack on Watermarking Processing operation Compression Rescaling Cropping Multiple watermarks
Background
Frame averaging Frame dropping Frame swapping Statistical analysis Interpolation
Department of Computer Science and Engineering The Chinese University of Hong Kong
Image Watermarking
Checksum Spread spectrum approach Hierarchical watermarking with DCT Wavelet-based watermarking DWT Digital Fourier Transform
Literature Review
Department of Computer Science and Engineering The Chinese University of Hong Kong
Video Watermarking
Raw video watermarking DFT DCT DWT
Watermarking I-frame (Mpeg-1,2) Video object watermarking (Mpeg-4)
Literature Review
New Algorithm
DWT-based Video Watermarking Scheme with
Scramble Watermark
Department of Computer Science and Engineering The Chinese University of Hong Kong
Discrete Wavelet Transform
Normalized to 256 X 256 pixel size Perform DWT for each frame
Department of Computer Science and Engineering The Chinese University of Hong Kong
Scene Change Detection Each scene is embedded with same watermark, it can
prevent attacker to remove the watermark by frame dropping
Independent watermark is used for successive different scene can prevent attacker collude with frames from completely different scenes
Mark with m1 Mark with m3 Mark with m0 Mark with m6
Scene change occur
Department of Computer Science and Engineering The Chinese University of Hong Kong
Watermark Preprocess Different frame use different watermark can make the
watermark resist to attack by frame averaging Hard to reconstruct the watermark without knowledge
85
64 0
1
2
4
5
6
73
Crop
Bit Decomposition
8 bit-planes
170
256
0
1
2
4
5
6
73
8 bit-planes
170
256
0
1
2
4
5
6
73Total 8 images is
obtained
m0
m7
Place the bit-planes side by side
170
256
Department of Computer Science and Engineering The Chinese University of Hong Kong
Watermark Embedding
C[i] = C[i] + 1 , if W[j] = 1 C[i] = C[i] , otherwise LL, HH is not watermark
HL1
LH1 HH1
HL2
HH2LH2
LL
LH
LH3 HH3
HL3
HL
HH
170
256
0
1
2
4
5
6
73
Watermark mi
Department of Computer Science and Engineering The Chinese University of Hong Kong
1. Video Frame256 X 256
3. DWT
DWT result frames
Original video frames4. Compare
2. Detect the scene change
5. Averaging the watermark get from different frames
Watermark mi
170
256m0
m1
m2
m4
m5
m6
m7m3
7. Get different part of W from different scene and
reconstruct the large image
170
256012
45673
6. Combine 8 bit-planes8564
8. Correlate and verify
Extracted Original
E O
Mark with m1 Mark with m3 Mark with m0 Mark with m6
Scene change occur
Watermark Detection
Department of Computer Science and Engineering The Chinese University of Hong Kong
Future Direction Implement and use do experiment on the
scheme Identifiable from very short segment of
video. Individual frames extracted from the video will also contain the copyright information
Change to blind watermarking scheme Make use of the object information
(information from Mpeg-4)
Department of Computer Science and Engineering The Chinese University of Hong Kong
Conclusion Video Watermarking is need due to
Copyright protection is essential Video watermarking is different from image
watermarking Brief review of current technologies DWT-based Video Watermarking Scheme
with Scramble Watermark Future Direction
The End