The Experts below are selected from a list of 5775 Experts worldwide ranked by ideXlab platform

Akio Mukaiyama - One of the best experts on this subject based on the ideXlab platform.

  • watermarking 3d Polygonal Meshes in the Mesh spectral domain
    Graphics Interface, 2001
    Co-Authors: Ryutarou Ohbuchi, Shigeo Takahashi, Takahiko Miyazawa, Akio Mukaiyama
    Abstract:

    Digital watermarking embeds a structure called watermark into the target data, such as image and 3D Polygonal models. The watermark can be used, for example, to enforce copyright and to detect tampering. This paper presents a new robust watermarking method that adds watermark into a 3D Polygonal Mesh in the Mesh's spectral domain. The algorithm computes spectra of the Mesh by using eigenvalue decomposition of a Laplacian matrix derived only from connectivity of the Mesh. Mesh spectra can be obtained by projecting coordinates of vertices onto the set of eigenvectors. A watermark is embedded by modifying the magnitude of the spectra. Watermarks embedded by using this method are resistant to similarity transformation, random noise added to vertex coordinates, Mesh smoothing, and partial resection of the Meshes.

Kokichi Sugihara - One of the best experts on this subject based on the ideXlab platform.

  • WSCG (Full Papers) - New spectral decomposition for 3D Polygonal Meshes and its application to watermarking
    2005
    Co-Authors: Kohei Murotani, Kokichi Sugihara
    Abstract:

    This paper present a generalization of a data analysis technique called a singular spectrum analysis (SSA). The original SSA is a tool for analyzing one-dimensional data such as time series, whereas our generalization is suitable for multi-dimensional data such as 3D Polygonal Meshes. One of applications of the proposed generalization are also shown. The application of the generalized SSA is a new robust watermarking method that adds a watermark to a 3D Polygonal Mesh. Watermarks embedded by our method are resistant to similarity transformations and random noises. Our method has the advantage in that it requires smaller calculation cost than other methods with nearly equal performance.

  • MATHEMATICAL ENGINEERING TECHNICAL REPORTS Generalized SSA and Its Applications to Watermarking 3D Polygonal Meshes
    2004
    Co-Authors: Kohei Murotani, Kokichi Sugihara
    Abstract:

    This paper presents a generalization of the singular spectrum analysis (SSA) and applies it to the construction of a new robust watermarking method that adds a watermark to a 3D Polygonal Mesh in the spectral domain. The SSA is originally designed as a tool for analyzing one-dimensional sequence such as time series, and hence it is not suitable for multi-dimensional data. In order to overcome this difficulty, we generalize the basic SSA in such a way that it can be used for the 3D Polygonal Meshes. Watermarks embedded by this method are resistant to similarity transformations and random noises.

  • towards shape representation using trihedral Mesh projections
    The Visual Computer, 2003
    Co-Authors: Llu Os Ros, Kokichi Sugihara, Federico Thomas
    Abstract:

    -coordinates} of the vertices are completely governed by the Z-coordinates assigned to four selected ones. This allows describing the spatial Polygonal Mesh with just its 2D projection plus the heights of four vertices. As a consequence, these projections essentially capture the “spatial meaning” of the given surface, in the sense that, whatever spatial interpretations are drawn from them, they all exhibit essentially the same shape.

  • shape representation using trihedral Mesh projections
    Discrete Geometry for Computer Imagery, 2002
    Co-Authors: Lluis Ros, Kokichi Sugihara, Federico Thomas
    Abstract:

    This paper explores the possibility of approximating a surface by a trihedral Polygonal Mesh plus some triangles at strategic places. The presented approximation has several attractive properties. It turns out that the Z-coordinates of the vertices are completely governed by the Z-coordinates assigned to four selected ones. This allows describing the spatial Polygonal Mesh with just its 2D projection plus the heights of four vertices. As a consequence, these projections essentially capture the "spatial meaning" of the given surface, in the sense that, whatever spatial interpretations are drawn from them, they all exhibit the same shape, up to some trivial ambiguities.

Akira Kawanaka - One of the best experts on this subject based on the ideXlab platform.

  • Triangular Mesh Geometry Coding with Multiresolution Decomposition Based on Structuring of Surrounding Vertices
    2008 IEEE International Symposium on Signal Processing and Information Technology, 2008
    Co-Authors: S Watanabe, Akira Kawanaka
    Abstract:

    In this paper, we propose a new Polygonal Mesh geometry coding scheme based on a process of structuring by acquiring surrounding vertices of the Polygonal Mesh one layer at a time. The structuring process begins by selecting the start vertex and proceeding by acquiring surrounding vertices of the Polygonal Mesh. As a result, we obtain a 2-D structured vertex table. Structured geometry data are generated according to the structured vertices and encoded by a multiresolution decomposition and space frequency quantization coding method. In our proposed scheme, the multiresolution decomposition uses the connectivity of the Polygonal Mesh. In addition, with a space frequency quantization coding scheme, we can reduce redundancies of decomposed coefficients at similar positions in different components of decomposition level. Experimental results show that the proposed scheme gives better coding performance at lower bit-rates than the usual schemes.

  • lifting wavelet coding with modified permutation for 2 d structured geometry of Polygonal Mesh
    International Symposium on Signal Processing and Information Technology, 2007
    Co-Authors: S Watanabe, Akira Kawanaka
    Abstract:

    A new coding scheme for geometry data of a Polygonal Mesh based on a structuring process of a 3-D model on a triangular lattice plane is proposed. A complex connectivity of the Polygonal Mesh is structured by assigning a vertex of the 3-D model to several nodes of triangular lattice plane with maintaining the connectivity. The geometry data of a vertex are arranged at the position of the representative node which is selected from the nodes to which the vertex is assigned. The structured geometry data with many undefined node points on a triangular lattice plane have to be coded efficiently. In this paper, we present a lifting wavelet based coding scheme for geometry data compression with permutation and coefficient modification process. The permutation process for an expanded node at an even location and the neighboring representative node arranges more representative nodes into the lower frequency band. The modification process uses the modified coefficients obtained from the coefficients of the adjacent representative nodes instead of the original coefficients to restrain increases in the decomposed coefficients with larger magnitude. Experimental results show that the proposed scheme gives better coding performance than usual schemes.

  • permuting and lifting wavelet coding for structured geometry data of 3 d Polygonal Mesh
    IEICE Transactions on Information and Systems, 2007
    Co-Authors: Akira Kawanaka, S Watanabe
    Abstract:

    This paper presents a lifting wavelet coding technique with permutation and coefficient modification processes for coding the structured geometry data of 3-D Polygonal Mesh model. One promising method for coding 3-D geometry data is based on the structure processing of a 3-D model on a triangle lattice plane, while maintaining connectivity. In the structuring process, each vertex may be assigned to several nodes on the triangular lattice plane. One of the nodes to which a vertex is assigned is selected as a representative node and the others are called expanded nodes. Only the geometry data of the vertices at the representative nodes are required for reconstructing the 3-D model. In this paper we apply a lifting wavelet transform with a permutation process for an expanded node at an even location in each decomposition step and the neighboring representative node. This scheme arranges more representative nodes into the lower frequency band. Also many representative nodes separated from the connective expanded nodes are made to adjoin each other in lower frequency bands, and the correlation between the representative nodes will be reduced by the following decomposition process. A process is added to use the modified coefficients obtained from the coefficients of the adjacent representative nodes instead of the original coefficients in the permutation process. This has the effect of restraining increases in the decomposed coefficients with larger magnitude. Some experiments in which the proposed scheme was applied to structured geometry data of a 3-D model with complex connectivity show that the proposed scheme gives better coding performance and the reconstructed models are more faithful to the original in comparison with the usual schemes.

  • Polygonal Mesh data compression based on triangular lattice structuring and wavelet transform
    International Conference on Image Processing, 2002
    Co-Authors: S Hirata, M Tsunoda, K Fukuda, Akira Kawanaka
    Abstract:

    In this paper, we describe a triangular lattice structuring method for 3D Polygonal Mesh data and a shape-adaptive wavelet transform of the structured geometry and textural data. Efficient representations of a 3D object data has attracted wide attention for transmission and storage of computer graphics data and interactive design in manufacturing. Polygonal Mesh data, which consist of connectivity information, geometry data and textural data, are often used for representing a 3D object in many applications. We propose a method for structuring the Polygonal Mesh data on a triangular lattice plane with expanded nodes. And a shape-adaptive wavelet coding method is applied to the structured geometry data considering the expanded nodes. Experimental results show that the proposed method gives better coding performance than the topologically assisted geometry compression scheme.

  • wavelet coding of Polygonal Mesh data based on triangular lattice structure with expanded nodes
    International Conference on Image Processing, 2001
    Co-Authors: M Tsunoda, K Fukuda, T Terasaki, Akira Kawanaka
    Abstract:

    Efficient representations of a 3D object shape and its textural data have attracted wide attention for the transmission of computer graphics data and for interactive design in manufacturing. Polygonal Mesh data, which consist of connectivity information, geometric data and textural data are often used for representing a 3D object in many applications. We propose a compression method for Polygonal Mesh data by structuring its geometric and textural data on a triangular lattice with expanded nodes. The structuralized geometric and textural data are compressed using a 2D signal coding method. Experimental results following from the application of the new method to Polygonal Mesh data show that the proposed scheme performs efficiently.

Ryutarou Ohbuchi - One of the best experts on this subject based on the ideXlab platform.

  • watermarking 3d Polygonal Meshes in the Mesh spectral domain
    Graphics Interface, 2001
    Co-Authors: Ryutarou Ohbuchi, Shigeo Takahashi, Takahiko Miyazawa, Akio Mukaiyama
    Abstract:

    Digital watermarking embeds a structure called watermark into the target data, such as image and 3D Polygonal models. The watermark can be used, for example, to enforce copyright and to detect tampering. This paper presents a new robust watermarking method that adds watermark into a 3D Polygonal Mesh in the Mesh's spectral domain. The algorithm computes spectra of the Mesh by using eigenvalue decomposition of a Laplacian matrix derived only from connectivity of the Mesh. Mesh spectra can be obtained by projecting coordinates of vertices onto the set of eigenvectors. A watermark is embedded by modifying the magnitude of the spectra. Watermarks embedded by using this method are resistant to similarity transformation, random noise added to vertex coordinates, Mesh smoothing, and partial resection of the Meshes.

Shigeo Takahashi - One of the best experts on this subject based on the ideXlab platform.

  • watermarking 3d Polygonal Meshes in the Mesh spectral domain
    Graphics Interface, 2001
    Co-Authors: Ryutarou Ohbuchi, Shigeo Takahashi, Takahiko Miyazawa, Akio Mukaiyama
    Abstract:

    Digital watermarking embeds a structure called watermark into the target data, such as image and 3D Polygonal models. The watermark can be used, for example, to enforce copyright and to detect tampering. This paper presents a new robust watermarking method that adds watermark into a 3D Polygonal Mesh in the Mesh's spectral domain. The algorithm computes spectra of the Mesh by using eigenvalue decomposition of a Laplacian matrix derived only from connectivity of the Mesh. Mesh spectra can be obtained by projecting coordinates of vertices onto the set of eigenvectors. A watermark is embedded by modifying the magnitude of the spectra. Watermarks embedded by using this method are resistant to similarity transformation, random noise added to vertex coordinates, Mesh smoothing, and partial resection of the Meshes.