在本篇論文中，我們提出一個姿勢健忘的盲式浮水印方法以達到三維網狀模型的著作權保護，以增進三維網狀浮水印對於抵抗姿勢變形的強健性。姿勢形變在遊戲和動畫產業中是很常見用於改變三維網狀模型姿勢的操作方法，但是對於大多數的浮水印方法而言，藏有浮水印的三維網狀模型會因姿勢形變造成浮水印偵測錯誤。因此，我們使用具有姿勢形變不敏感性的局部形狀直徑(LSD)來藏匿浮水印以達到抵抗姿勢形變。給予一個三維網狀模型，首先我們沿著頂點的相反法向量方向射出數個射線，再將所有射線的長度做加權平均後即是頂點的LSD，接著依據LSD的分佈，我們將所有頂點分成數個頂點集合，最後我們藉著調整成對的集合大小差異以修改LSD來藏匿浮水印。從實驗結果中可看出所提出的方法對於姿勢形變具有強健性，而且也可以抵抗幾何和拓樸攻擊，包含頂點重新排列、相似度轉換、雜訊添加、表面平滑化、頂點座標量化、模型簡單化和模型複雜化等攻擊。

In this thesis, a pose-oblivious blind watermarking method is proposed for copyright protection of three-dimensional (3D) mesh models. We aim to enhance the robustness of 3D mesh watermarking against pose deformations, which are common operations in game and animation industries to change the poses of 3D mesh models. The pose-oblivious signature, namely local shape diameter (LSD), is exploited for watermarking to achieve the insensitivity to pose deformations. Given a 3D mesh model, we first measure the LSD of all vertices by shooting several rays along inward-normal direction of each vertex and averaging the weighted length of all the rays. Then, all vertices are classified into several vertex sets according to the LSD distribution. Finally, we embed the watermark by modifying the LSD to adjust difference between the cardinalities of pairs of vertex sets. Experimental results show that the proposed method is robust against pose deformations. Moreover, it demonstrates good resistance to geometry and topology attacks, such as vertex reordering, similarity transform, noise addition, smoothing, quantization, simplification, and subdivision.

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