| Summary: | 碩士 === 中華大學 === 資訊工程學系碩士班 === 91 === The conventional public watermarking systems address the problems of invisible watermark embedding technique and robust resistance for various kinds of attacks including the compression, filtering, and geometric transformation etc. However, some emerging counterfeit attacks make the authentication process difficult and then the rightful ownership is hard to be claimed. Therefore, the watermark encryption problem should be considered in developing the public watermarking system to resist the counterfeit attacks. In this thesis, a two-stage watermark embedding technology is developed to construct a secure watermarking technique for the object-oriented video coding system. In the first stage, the MD5 secure hash algorithm and the RSA cryptographic technique are applied to hide the watermarks into the image feature coefficients such that the watermarks may be encrypted securely. In the second stage, another watermark is embedded during the SPIHT encoding process for the partitioned video objects. By specifying the encoding priorities of the partitioned objects and the bitplane-by-bitplane shifting of these objects according to their encoding priorities, the watermark may be inserted into the empty bitplanes. Through the two-stage watermark extraction and similarity measure processes, the rightful ownership can be authenticated. Furthermore, by comparing the extracted watermarks among the wavelet subbands, the image regions that are modified by the counterfeiter may be identified. In addition, the JND functions generated by the Human Visual System (HVS) are utilized to embed the watermarks with the largest strength under the visual invisible requirement.
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