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