| Summary: | 碩士 === 國立交通大學 === 資訊管理所 === 91 === A good digital image watermark system consists of six characteristics namely robustness, invisible, unambiguous, statically undetectable, blindness and security. To archive the better security control, watermarks should not be detected or removed by unauthorized users especially if the algorithm of embedding & detecting watermarks are open to the public. This research discusses how to ensure the better security of wavelet-based watermark system by using multiple wavelet filters in the processes of embedding & detecting. It is found that misjudgment may occur while using multiple set of filters in the processes of embedding watermarks. In addition, filters generated by the formula under same constraints have similar performance. To prevent the misjudgment of the copyright verification, the differences between filters should be examined before embedding watermark, or using filters created by different formulas.
|
|---|
