• Journal of Korea Multimedia Society
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• v.8 no.12
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• pp.1572-1580
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• 2005

The common requirements for watermarking are usually invisibility, robustness, and capacity. We proposed the watermarking for 3D mesh model based on projection onto convex sets for invisibility and robustness among requirements. As such, a 3D mesh model is projected alternatively onto two convex sets until it converge a point. The robustness convex set is designed to be able to embed watermark into the distance distribution of vertices. The invisibility convex set is designed for the watermark to be invisible based on the limit range of vertex movement. The watermark can be extracted using the decision values and index that the watermark was embedded with. Experimental results verify that the watermarked mesh model has both robustness against mesh simplification, cropping, affine transformations, and vertex randomization and invisibility.

• Journal of Korea Multimedia Society
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• v.7 no.1
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• pp.80-90
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• 2004

Watermarking algorithm for 3D mesh model using EGI distribution of each patch is proposed. The proposed algorithm divides a 3D mesh model into 6 patches to have the robustness against the partial geometric deformation. Plus, it uses EGI distributions as the consistent factor that has the robustness against the topological deformation. To satisfy both geometric and topological deformation, the same watermark bits for each subdivided patch are embedded by changing the mesh normal vectors. Moreover, the proposed algorithm does not need not only the original mesh model but also the resampling process to extract the watermark. Experimental results verify that the proposed algorithm is imperceptible and robust against geometrical and topological attacks.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.11C
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• pp.1592-1599
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• 2004

In this paper, we proposed the 3D mesh watermarking using projection onto convex sets (POCS). 3D mesh is projected iteratively onto two constraint convex sets until it satisfy the convergence condition. These sets consist of the robustness set and the invisibility set that designed to embed watermark Watermark is extracted without original mesh by using the decision values and the index that watermark is embedded. Experimental results verified that the watermarked mesh have the robustness against mesh simplification, cropping, affine transformation, and vertex randomization as well as the invisibility.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.43 no.2 s.308
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• pp.81-92
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• 2006

This paper proposes a robustness watermarking for 3D mesh model based on projection onto convex sets (POCS). After designing the convex sets for robustness and invisibility among some requirements for watermarking system, a 3D-mesh model is projected alternatively onto two constraints convex sets until the convergence condition is satisfied. The robustness convex set are designed for embedding the watermark into the distance distribution of the vertices to robust against the attacks, such as mesh simplification, cropping, rotation, translation, scaling, and vertex randomization. The invisibility convex set are designed for the embedded watermark to be invisible. The decision values and index that the watermark was embedded with are used to extract the watermark without the original model. Experimental results verify that the watermarked mesh model has invisibility and robustness against the attacks, such as translation, scaling, mesh simplification, cropping, and vertex randomization.

• Journal of Broadcast Engineering
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• v.9 no.1
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• pp.64-73
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• 2004

A robust watermarking algorithm is proposed for 3D mesh models. Watermark is inserted into the 2D image which is extracted from the target 3D model. Each Pixel value of the extracted 2D image represents a distance from the predefined reference points to the face of the given 3D model. This extracted image is defined as “range image” in this paper. Watermark is embedded into the range image. Then, watermarked 3D mesh is obtained by modifying vertices using the watermarked range Image. In extraction procedure, the original model is needed. After registration between the original and the watermarked models, two range images are extracted from each 3D model. From these images. embedded watermark is extracted. Experimental results show that the proposed algorithm is robust against the attacks such as rotation, translation, uniform scaling, mesh simplification, AWGN and quantization of vertex coordinates.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.32 no.12C
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• pp.1194-1202
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• 2007

In this paper, we proposed a blind watermarking algorithm to apply to the rapid prototyping system. The 3D mesh model is used in the step of the CAD modeling before the making of the prototype system of the rapid prototyping system. STL type mesh modeling which is used in this system reduces the error of the system and improves the accuracy of the system. In the step of the CAD modeling, some transformations which do not change the model accuracy are used, but some transformations which change the model accuracy are not used because the mesh model error is related to the accuracy of the prototype system. Most watermarking algorithms embedded a specific random noise as the watermark information into the model. These kinds of the algorithms are not proper to the 3D model watermarking. The proposed algorithm can be used for the accurate prototyping system because it does not change the model after the watermark embedding This means it can be used for the copyright marking and the data integrity.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.42 no.1
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• pp.67-78
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• 2005

We proposed a blind watermarking for 3D mesh model using the patch CEGIs. The CEGI is the 3D orientation histogram with complex weight whose magnitude is the mesh area and phase is the normal distance of the mesh from the designated origin. In the proposed algorithm we divide the 3D mesh model into the number of patch that determined adaptively to the shape of model and calculate the patch CEGIs. Some cells for embedding the watermark are selected according to the rank of their magnitudes in each of patches after calculating the respective magnitude distributions of CEGI for each patches of a mesh model. Each of the watermark bit is embedded into cells with the same rank in these patch CEGI. Based on the patch center point and the rank table as watermark key, watermark extraction and realignment process are performed without the original mesh. In the rotated model, we perform the realignment process using Euler angle before the watermark extracting. The results of experiment verify that the proposed algorithm is imperceptible and robust against geometrical attacks of cropping, affine transformation and vertex randomization as well as topological attacks of remeshing and mesh simplification.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.29 no.4C
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• pp.472-484
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• 2004

We proposed 3D mesh watermarking algorithm using CEGI distribution. In the proposed algorithm, we divide a 3D mesh of VRML data into 6 patches using distance measure and embed the same watermark bits into the normal vector direction of meshes that mapped into the cells of each patch that have the large magnitude of complex weight of CEGI. The watermark can be extracted based on the known center point of each patch and order information of cell. In an attacked model by affine transformation, we accomplish the realignment process before the extraction of the watermark. Experiment results exhibited the proposed algorithm is robust by extracting watermark bit for geometrical and topological deformed models.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.18 no.1
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• pp.149-159
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• 2008

In this paper, we propose a blind watermarking algorithm of 3d mesh model using spherical parameterization. Spherical parameterization is a useful method which is applicable to 3D data processing. Especially, orthogonal coordinate can not analyse the feature of the vertex coordination of the 3D mesh model, but this is possible to analyse and process. In this paper, the centroid center of the 3D model was set to the origin of the spherical coordinate, the orthogonal coordinate system was transformed to the spherical coordinate system, and then the spherical parameterization was applied. The watermark was embedded via addition/modification of the vertex after the feature analysis of the geometrical information and topological information. This algorithm is robust against to the typical geometrical attacks such as translation, scaling and rotation. It is also robust to the mesh reordering, file format change, mesh simplification, and smoothing. In this case, the this algorithm can extract the watermark information about $90{\sim}98%$ from the attacked model. This means it can be applicable to the game, virtual reality and rapid prototyping fields.

• Journal of Korea Multimedia Society
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• v.9 no.12
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• pp.1596-1606
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• 2006

There has been more increased the development of 3D technique since many 3D contents of 3D graphic model, 3D mobile/computer game, and 3D CAD have been serviced in Web or industry fields. Therefore, the watermarking system is more required to protect the copyright for 3D contents. Currently there has been researched about the watermarking for 3D graphic model of mesh or NURBS. However, watermarking technique based on CAD design drawing leaves something to be desired yet. This paper proposed the watermarking technique for 3D CAD design drawing using Line and Arc components. After drawing out Line and Arc components from designed drawing, we embed the watermark into both the length of Line component and the radius of Arc component. Experimental results verified that the proposed algorithm satisfies the transparency about watermarked drawing and also has the robustness against several attacks by using public CAD tool.