Robust Motion Watermarking based on Multiresolution Analysis EUROGRAPHICS
Robust Motion Watermarking based on Multiresolution Analysis EUROGRAPHICS 2000 Speaker: 彭任右, GAME Lab Date: 4/18/2005 Alvin/GAME Lab. /CSIE/NDHU Robust Motion Watermarking based on Multiresolution Analysis
Outline Introduction Framework Results Conclusions & Future Work Alvin/GAME Lab. /CSIE/NDHU Robust Motion Watermarking based on Multiresolution Analysis 2
Introduction Multiresolution Representation A coarse base signal. A hierarchy of motion displacement maps. Spread Spectrum Embed a watermark into a wide range of frames in a motion signal. Watermarking Perturbing larger detail coefficients in displacement maps. Alvin/GAME Lab. /CSIE/NDHU Robust Motion Watermarking based on Multiresolution Analysis 3
Displacement Map Reduction Smoothing followed by down-sampling Expansion By subdividing Up-sampling followed by smoothing M = M’ ⊕ D Alvin/GAME Lab. /CSIE/NDHU Robust Motion Watermarking based on Multiresolution Analysis 4
Multiresolution Representation M(N):The original motion M(0):The coarsest signal Original Signal Alvin/GAME Lab. /CSIE/NDHU M(3) M(2) Robust Motion Watermarking based on Multiresolution Analysis M(1) M(0) 5
Watermarking Perturb large coefficient (robust) with small magnitude (imperceptible). Alvin/GAME Lab. /CSIE/NDHU Robust Motion Watermarking based on Multiresolution Analysis 6
Watermark Generation Watermark w = {w 1, …, wm} wi is sampled independently from a normal distribution with zero mean and unit variance. Use MD 5 (Cryptographic hash function) to seed random number generator. Alvin/GAME Lab. /CSIE/NDHU Robust Motion Watermarking based on Multiresolution Analysis 7
Watermark Extraction Alvin/GAME Lab. /CSIE/NDHU Robust Motion Watermarking based on Multiresolution Analysis 8
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 9
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 10
Results Alvin/GAME Lab. /CSIE/NDHU Robust Motion Watermarking based on Multiresolution Analysis 11
Results false-positive The probability of incorrectly asserting that the data is watermarked. Alvin/GAME Lab. /CSIE/NDHU Robust Motion Watermarking based on Multiresolution Analysis 12
Results Alvin/GAME Lab. /CSIE/NDHU Robust Motion Watermarking based on Multiresolution Analysis 13
Conclusions & Future Work A practical method to watermark a motion. Two novel ideas: Spread Spectrum and Multiresolution Representation Robust to various signal processing Resilient to more complex motion editing. Alvin/GAME Lab. /CSIE/NDHU Robust Motion Watermarking based on Multiresolution Analysis 14
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