Multimedia Security Digital 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 Watermark Or Confidence measure Test Image Ì Watermark W and/or original image I Secret / public key K Watermarking Algorithm Watermarked Image Ì Stego-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 m 1 Mark with m 3 Mark with m 0 Mark with m 6 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 Crop Bit Decomposition 8 bit-planes bit-planes Total 8 images is obtained m0m0 m7m7 Place the bit-planes side by side

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 HL 1 LH 1 HH 1 HL 2 HH 2 LH 2 LL LH LH 3 HH 3 HL 3 HL HH Watermark m i

Department of Computer Science and Engineering The Chinese University of Hong Kong 1. Video Frame 256 X DWT DWT result frames Original video frames 4. Compare 2. Detect the scene change 5. Averaging the watermark get from different frames Watermark m i m0m0 m1m1 m2m2 m4m4 m5m5 m6m6 m7m7 m3m3 7. Get different part of W from different scene and reconstruct the large image Combine 8 bit-planes Correlate and verify ExtractedOriginal EO Mark with m 1 Mark with m 3 Mark with m 0 Mark with m 6 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

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