基于DCT的战机3D模型多重水印算法

Multiple Watermark Algorithm on Fighter's 3D Model Based on DCT

为有效保证战斗武器装备3D(Three Dimensions)模型的独创性与安全性,以战机3D模型为例,利用数字水印技术,将自身版权信息嵌入其中,并提出了一种基于DCT(Discrete Cosine Transform)变换的3D网格模型多重水印算法。该算法将3D模型进行仿射变换,以模型重心为三维笛卡尔坐标系原点,分别抽取3D模型经主元分析后的顶点在XOY、XOZ、YOZ 3个2D(Two Dimensions)平面上的投影坐标数组。针对3组2D离散信号分别进行2D-DCT变换,并将2D数字图像水印分别嵌入到3组变换后的中频系数中。多重水印的嵌入,使其在仿射不变空间下,实现了3D模型对简化、噪声、剪切等攻击的鲁棒性。实验结果表明,该方法不仅具有较强的鲁棒性,而且具有良好的水印不可见性,进而有效防止了战斗武器装备模型的非法二次开发或应用。

In order to protect the 3D （Three Dimensions） models＇ originality and security of weaponaries effectively,we take fighter＇s 3D model as an example,and adopt digital watermark technique to embed the copyright information.A multiple watermark plan on 3D mesh model based on DCT（Discrete Cosine Transform） is proposed.Firstly,put 3D model to affined transform,and consider the center of gravity of 3D model as the base point of three-dimensional Cartesian coordinate,extract the vertex＇s coordinate data of 3D model after principal elements＇ analysis projected on three 2D （Two Dimensions）planes of XOY、XOZ、YOZ.Take these three sets of two-dimensional discrete signal into DCT transform and embed two-dimensional digital watermark into three sets＇ middle-frequency coefficients after transform.Multiple watermark embedding achieves 3D model＇s robustness to simplification,noise and cut and so on under fixed-affine space.Experiments prove that this approach has strong robustness and fine watermark-invisibility.Thus,this way avoids unlawful second-hand exploitation or application availably.