by Yeung Siu Wai. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2000. / Includes bibliographical references (leaves 59-[62]). / Abstracts in English and Chinese. / Chapter 1 --- Introduction --- p.1 / Chapter 2 --- Background --- p.4 / Chapter 2.1 --- Properties of a digital watermarking system --- p.5 / Chapter 2.2 --- Digital watermarking in still images: Spatial-domain vs Frequency- domain --- p.7 / Chapter 2.3 --- Capacity in digital watermarking --- p.8 / Chapter 3 --- A watermarking system --- p.10 / Chapter 3.1 --- Implementation of a watermarking system --- p.10 / Chapter 3.1.1 --- Embedding watermark --- p.11 / Chapter 3.1.2 --- Detecting watermark --- p.14 / Chapter 3.2 --- Robustness testing on the watermarking system --- p.18 / Chapter 3.3 --- Geometric attacks to the watermark system --- p.18 / Chapter 3.3.1 --- "The three distortions: Translation, Dilation and Rotation" --- p.19 / Chapter 3.3.2 --- The commutative property of rotation and dilation --- p.25 / Chapter 3.3.3 --- Implementation of geometric transform --- p.25 / Chapter 4 --- General Defense on Geometric Distortions --- p.28 / Chapter 4.1 --- Special designed watermark --- p.29 / Chapter 4.1.1 --- Ring-shaped watermark --- p.29 / Chapter 4.1.2 --- Phase Taylor invariance --- p.30 / Chapter 4.1.3 --- "Rotation, dilation and translation invariant watermark" --- p.31 / Chapter 4.2 --- Distortion detection --- p.34 / Chapter 4.2.1 --- Brute-force method --- p.35 / Chapter 4.2.2 --- Interactive method --- p.37 / Chapter 5 --- Specific Defense in Geometric Distortions - Phase angle com- parison --- p.43 / Chapter 5.1 --- Translation Detection --- p.44 / Chapter 5.2 --- Dilation Detection --- p.46 / Chapter 5.3 --- Rotation Detection --- p.49 / Chapter 6 --- Further work --- p.54 / Chapter 6.1 --- Large scale distortion detection --- p.54 / Chapter 6.2 --- Mixed geometric distortions --- p.55 / Chapter 7 --- Conclusion --- p.57 / Bibliography --- p.59