Robust Motion Watermarking based on Multiresolution Analysis

EUROGRAPHICS 2000Speaker: 彭任右 , GAME Lab

Date: 4/18/2005

Alvin/GAME Lab./CSIE/NDHU

Robust Motion Watermarking based on Multiresolution Analysis

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Outline

IntroductionFrameworkResultsConclusions & Future Work

Alvin/GAME Lab./CSIE/NDHU

Robust Motion Watermarking based on Multiresolution Analysis

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Introduction

Multiresolution RepresentationA coarse base signal.A hierarchy of motion displacement maps.

Spread SpectrumEmbed a watermark into a wide range of frames in a motion signal.

WatermarkingPerturbing larger detail coefficients in displacement maps.

Alvin/GAME Lab./CSIE/NDHU

Robust Motion Watermarking based on Multiresolution Analysis

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Displacement Map

ReductionSmoothing followed by down-sampling

ExpansionBy subdividingUp-sampling followed by smoothing

M = M’ ⊕ D

Alvin/GAME Lab./CSIE/NDHU

Robust Motion Watermarking based on Multiresolution Analysis

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Multiresolution Representation

M(N)： The original motionM(0)： The coarsest signal

Original Signal M(3) M(2) M(1) M(0)

Alvin/GAME Lab./CSIE/NDHU

Robust Motion Watermarking based on Multiresolution Analysis

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WatermarkingPerturb large coefficient (robust) with small magnitude (imperceptible).

Alvin/GAME Lab./CSIE/NDHU

Robust Motion Watermarking based on Multiresolution Analysis

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Watermark Generation

Watermark w = {w1, …, wm}

wi is sampled independently from a normal distribution with zero mean and unit variance.Use MD5 (Cryptographic hash function) to seed random number generator.

Alvin/GAME Lab./CSIE/NDHU

Robust Motion Watermarking based on Multiresolution Analysis

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Watermark Extraction

Alvin/GAME Lab./CSIE/NDHU

Robust Motion Watermarking based on Multiresolution Analysis

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Similarity

Remove outliers which differences from the mean value are greater than a threshold.Linear Correlation

Alvin/GAME Lab./CSIE/NDHU

Robust Motion Watermarking based on Multiresolution Analysis

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Motion Aligning

Resist the Crop or Non-uniformly Scale.Using the Dynamic Time Warping scheme.

Alvin/GAME Lab./CSIE/NDHU

Robust Motion Watermarking based on Multiresolution Analysis

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Results

Alvin/GAME Lab./CSIE/NDHU

Robust Motion Watermarking based on Multiresolution Analysis

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Resultsfalse-positive

The probability of incorrectly asserting that the data is watermarked.

Alvin/GAME Lab./CSIE/NDHU

Robust Motion Watermarking based on Multiresolution Analysis

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Results

Alvin/GAME Lab./CSIE/NDHU

Robust Motion Watermarking based on Multiresolution Analysis

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Conclusions & Future Work

A practical method to watermark a motion.Two novel ideas: Spread Spectrum and Multiresolution RepresentationRobust to various signal processingResilient to more complex motion editing.