• Title/Summary/Keyword: 삼차원 메쉬

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Texture Image Rearrangement for Texture Coordinate Coding of Three-dimensional Mesh Models (삼차원 메쉬 모델의 텍스처 좌표 부호화를 위한 텍스처 영상의 재배열 방법)

  • Kim, Sung-Yeol;Ho, Yo-Sung
    • Proceedings of the IEEK Conference
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    • 2005.11a
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    • pp.963-966
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    • 2005
  • Previous works related to texture coordinate coding of the three-dimensional(3-D) mesh models employed the same predictor as the geometry coder. However, discontinuities in the texture coordinates cause unreasonable prediction. Especially, discontinuities become more serious for the 3-D mesh model with a non-atlas texture image. In this paper, we propose a new coding scheme to remove discontinuities in the texture coordinates by reallocating texture segments according to a coding order. Experiment results show that the proposed coding scheme outperforms the MPEG-4 3DMC standard in terms of compression efficiency. The proposed scheme not only overcome the discontinuity problem by regenerating a texture image, but also improve coding efficiency of texture coordinate compression.

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Color Data Compression for Three-dimensional Mesh Models Using Connectivity and Geometry Information (연결성 정보와 기하학 정보를 이용한 삼차원 메쉬 모델의 색상 정보 압축 방법)

  • Yoon, Young-Suk;Kim, Sung-Yeol;Ho, Yo-Sung
    • Proceedings of the IEEK Conference
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    • 2006.06a
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    • pp.745-746
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    • 2006
  • In this paper, we propose a new predictive coding scheme for color data of three-dimensional (3-D) mesh models. We exploit connectivity and geometry information to improve coding efficiency. After ordering all vertices in a 3-D mesh model with a vertex traversal technique, we employ a geometry predictor to compress the color data. The predicted color can be acquired by a weighted sum of reconstructed colors for adjacent vertices using both angles and distances between the current vertex and adjacent vertices.

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Real-Time Pencil Rendering (실시간 연필 렌더링)

  • Lee, Hyun-Jun;Kwon, Sung-Tae;Lee, Seong-Yong
    • Journal of the Korea Computer Graphics Society
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    • v.11 no.4
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    • pp.1-10
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    • 2005
  • 본 논문에서는 주어진 삼차원 메쉬를 실시간에서 연필화로 표현하는 방법을 소개한다. 이를 위해 본 논문에서는 연필화의 특징을 분석한 후 분석된 특징들을 빠르고 간단하게 모사하여 표현하는 알고리즘을 제시한다. 이 알고리즘은 크게 윤곽선을 그리는 방법과 내부를 그리는 방법으로 나뉘며, 제시된 모든 알고리즘은 그래픽스 하드웨어를 이용하여 실시간으로 동작한다. 우선 물체의 윤곽선을 그리기 위해 사람이 윤곽선을 그릴 때의 특징을 분석하여 실제의 윤곽선과 비교해 약간의 오차를 지니면서 여러번 겹쳐 그린 듯한 윤곽선을 만들어 내는 방법을 제시한다. 또한 물체의 내부를 그리기 위해서 먼저 연필의 특징을 잘 반영하는 텍스쳐를 만든 후 이를 물체의 표면에 매핑시켜 물체의 특징을 연필화풍으로 잘 표현하는 방법을 제시한다. 이 과정에서 연필화의 느낌을 강조하기 위해 물체가 그려지는 종이의 질감을 표현하는 방법과 물체의 명암비를 조정하는 방법 역시 제시한다.

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Mantissa Chunking Algorithm for the Compression and Progressive Transmission of 3D Mesh Models (삼차원 메쉬 모델의 압축 및 점진적 전송을 위한 가수부 분할 기법)

  • Kim, D.S.;Chung, J.Y.;Kim, H.
    • Korean Journal of Computational Design and Engineering
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    • v.7 no.2
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    • pp.81-88
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    • 2002
  • Transmission of 3D shape model through Internet has become one of the hottest issues in these days. Presented in this paper is a new approach for the rapid transmission of the geometry data of the shape model. By analyzing the important three factors, the shape fidelity, the file size, and the decompression time, for the compression, we point out the potential problems of previous approaches of using the deltas between consecutive vertices and propose an alternative of directly using the position values of vertices of the model. It turns out that the proposed approach has smaller file size, has lesser distortion in the model, and the decompression is faster.

High Dynamic Range Compression using 3D Mesh Processing (삼차원 메쉬 처리를 이용한 고명암 대비 압축)

  • Im, Jong-Guk;Lee, Yun-Jin;Lee, Seung-Yong
    • Journal of the Korea Computer Graphics Society
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    • v.8 no.3
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    • pp.9-16
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    • 2002
  • Recently, high dynamic range (HDR) compression has attracted much attention due to the wide availability of HDR images. In this paper, we present an HDR compression method using a progressive image, which is a multi-level image representation based on a progressive mesh. An HDR image can be decomposed into a base image and a sequence of details by conversion into a progressive image. This decomposition provides a good structure to highly compress the dynamic range while preserving image details. The base image and larger details are considerably scaled down but smaller details are slightly scaled down. Experimental results show that our method successfully generates HDR compressed images without halo artifacts by controlling two intuitive parameters.

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FEM Modeling Automation of Machine Tools Structure (공작기계 구조물의 전산 모델링 자동화)

  • Lee, Chan-Hong;Ha, Tae-Ho;Lee, Jae-Hak
    • Journal of the Korean Society for Precision Engineering
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    • v.29 no.10
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    • pp.1043-1049
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    • 2012
  • The FEM analysis of machine tools is the general analysis process to evaluate machine performance in the industry for a long time. Despite advances in FEM software, because of difficult simplicity of CAD drawing, little experience of joints stiffness modeling and troublesome manual contact area divide for bindings, the industry designers think the FEM analysis is still an area of FEM analysis expert. In this paper, the automation of modeling process with simplicity of drawing, modeling of joints and contact area divide is aimed at easy FEM analysis to enlarge utilization of a virtual machine tools. In order to verify the effects of modeling automation, a slant bed type model with tilting table is analyzed. The results show FEM modeling automation method only needed 45 minutes to complete the whole modeling process, while manual modeling method requires almost one month with 8200 calculations for coordinate transformations and stiffness data input.

Development of Stiffness Estimation Algorithm for Nonlinear Static Analysis of Bilinear Material Model (전단벽 모형화 방법에 따른 구조해석 신뢰성에 대한 고찰)

  • Jung, Sung-Jin;Park, Se-Hee
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.18 no.3
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    • pp.718-723
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    • 2017
  • When structural analysis modelling methods of practical fields are investigated, a slab is generally modeled by a finite element mesh using plate elements and a shear wall is modeled using a shell element or wall element for 3-D structural analysis. The point worthy of notice in this practice is that a shear wall is modelled using only one wall or shell element divided by floors and column lines to produce structural models. The modeling method like this can cause analysis errors according to the type of computer programs in use, and these errors reduce the reliability of the analysis results. Therefore, to secure the reliability of structural analysis, studies of the causes of errors and finding reasonable modeling methods are necessary. In this study, the causes of analysis errors according to the modelling methods of a shear wall, which are used in practical fields, were investigated and some considering matters for modelling a shear wall are presented to reduce the analysis errors on these analysis results.

An Extended Modal Warping Approach to Real-Time Simulation of Thin Shells (얇은 쉘의 실시간 시뮬레이션을 위한 모달 와핑 기법의 확장)

  • Choi, Min-Gyu;Woo, Seung-Yong;Ko, Hyeong-Seok
    • Journal of Korea Game Society
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    • v.7 no.2
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    • pp.11-20
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    • 2007
  • This paper proposes a real-time simulation technique for thin shells undergoing large deformation. Shells are thin objects such as leaves and papers that can be abstracted as 2D structures. Development of a satisfactory physical model that runs in real-time but produces visually convincing animation of thin shells has been remaining a challenge in computer graphics. Rather than resorting to shell theory which involves the most complex formulations in continuum mechanics, we adopt the energy functions from the discrete shells proposed by Grinspun et al. For real-time integration of the governing equation, we develop a modal warping technique for shells. This new simulation framework results from making extensions to the original modal warping technique which was developed for the simulation of 3D solids. We report experimental results, which show that the proposed method runs in real-time even for large meshes, and that it can simulate large bending and/or twisting deformations with acceptable realism.

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Oriental Black Ink Rendering System (수묵화 렌더링 시스템)

  • Jeong, Kyu-Man;Lee, Seung-Yong
    • Journal of the Korea Computer Graphics Society
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    • v.15 no.2
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    • pp.19-34
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    • 2009
  • This paper presents an automatic rendering system for 3D meshes which generates images in the style of oriental black ink painting. In this paper, we analyze the characteristics of black ink painting and present some requirements for our black ink rendering system. Then we survey the steps used by artists to create black ink paintings. Based on the analysis of drawing steps, we propose a black ink rendering system which reproduces the key features of black ink painting through three sub-systems: the feature line layer, the interior shading layer, and the media layer. The main contribution of this paper is to introduce new methods which generate realistic and natural results very fast while any simulation methods are not used to satisfy real-time performance. We describe our implementation of each of these, and demonstrate our results in the major three styles of black ink painting: the outline style, the spontaneous style, and the outline-spontaneous style. Our system renders 3D models of moderate complexity at interactive frame rates. As a result, we expect that our system can be directly applied to real-time applications such as computer games and virtual environments.

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