近年來由於網路的快速發展，網路頻寬的加大加速，使得數位資料的散佈變得更加地容易且快速。無疑地，網路技術的發展給人們帶來取多的便利，但是資訊安全的問題卻隨之產生。為了因應此問題，數位浮水印的技術便由此誕生了。在我們三維圖學領域最常用到的數位資料便是三維網格模型，為了保護我們辛苦建出的三維網格模型，不被不肖人士盜用或是竄改，我們便把浮水印的技術加進三維網格模型，以保護我們的著作權。

本論文將提出新的朝向盲目流程的強健型浮水印系統，我們將網格特徵值作為基礎，找出網格的特徵區域。接著，我們將使用Laplacian Coordinate Deform把浮水印嵌入區域中。最後我們將會把必要的資訊儲存成金鑰，以便我們能進行浮水印的取出。由於我們所找的到特徵區域能抵抗各種攻擊，因此我們欲取出浮水印時，只要找到網格的特徵區域，再參考金鑰的資訊，經過資料比對之後便能取出我們所藏入的浮水印資訊。

In this thesis, a semi-blind and semi-reversible robust watermarking scheme for 3D polygon models is proposed. Watermarking provides a mechanism for copyright protection of digital media by embedding information identifying the owner in the data. The proposed approach is based on the concept of spread spectrum to embed watermarks in the spatial domain. Comparing to related spread-spectrum based watermarking approaches which perturbs vertices along the direction of the surface normal, the proposed approach perturbs vertices by deforming local shapes along the direction of differential coordinates which lead to resulting in a more imperceptible embedding results. In addition, the proposed approach is robust to withstand a variety of attacks (including rotation, translation, uniform scaling, noise, smoothing, simplification, and even deformation) and is able to semi-reverse the cover models. The experimental results show that the proposed approach can withstand more attacks than other state-of-the-art approaches.

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