• Title/Summary/Keyword: 삼차원 메쉬

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

  • Yoon, Young-Suk;Ho, Yo-Sung
    • Journal of the Institute of Electronics Engineers of Korea CI
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    • v.45 no.3
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    • pp.160-174
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    • 2008
  • In this paper, we propose new coding techniques for photometry data of three-dimensional(3-D) mesh models. We make a good use of geometry and connectivity information to improve coding efficiency of color, normal vector, and texture data. First of all, we determine the coding order of photometry data exploiting connectivity information. Then, we exploit the obtained geometry information of neighboring vortices through the previous process to predict the photometry data. For color coding, the predicted color of the current vertex is computed by a weighted sum of colors for adjacent vortices considering geometrical characteristics between the current vortex and the adjacent vortices at the geometry predictor. For normal vector coding, the normal vector of the current vertex is equal to one of the optimal plane produced by the optimal plane generator with distance equalizer owing to the property of an isosceles triangle. For texture coding, our proposed method removes discontinuity in the texture coordinates and reallocates texture image segments according to the coding order. Simulation results show that the proposed compression schemes provide improved performance over previous works for various 3-D mesh models.

Sequential 3D Mesh Coding using Wave Partitioning (파동분할 방식의 순차적 삼차원 메쉬 압축 부호화)

  • 김태완;안정환;임동근;호요성
    • Proceedings of the IEEK Conference
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    • 2001.09a
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    • pp.125-128
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    • 2001
  • 본 논문은 파동분할(Wave partitioning) 방식을 이용한 순차적(Sequential) 메쉬 부호화 방식을 제안한다. 파동분할 방식은 호수에 물방울이 퍼져 나가는 자연 원리를 이용하여 초기 삼각형의 주위에 삼각형을 덧붙여 가면서 하나의 SPB(Small Processing Block)을 만들어내는 방식이다. 이 방식을 이용하여 하나의 모델을 서로 독립적인 SPB로 분할하고, 각각의 SPB 내에서 초기 삼각형을 중심으로 그것에 덧붙여진 삼각형에 의해 만들어진 원 또는 반원을 찾는다. 또한 그 원주를 따라 순차적으로 꼭지점을 구하면 각각의 꼭지점들은 일정한 패턴으로 늘어서게 되고, 이를 이용하여 연결성 정보 없이 부가 정보만 이용하여 모델을 순차적으로 무손실 부호화한다.

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A Voxel Data Compression Using Skeleton (스켈레톤을 이용한 삼차원 체적소 데이터의 부호화)

  • 송인욱;김창수;이상욱
    • Proceedings of the IEEK Conference
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    • 2000.09a
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    • pp.273-276
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    • 2000
  • 3차원 영상은 2차원 영상에 비해 데이터량이 매우 방대하다. 따라서 3차원 데이터를 효율적으로 압축하는 것은 매우 중요하다. 현재까지 대부분의 연구는 데이터량이 체적소(voxel)에 비해 월등히 적은 메쉬(mesh)를 기반으로 하여 이루어져 왔다. 하지만, 메쉬를 이용한 데이터 압축의 경우 체적소에 비해 데이터 자체의 규칙성이 떨어져 체적소를 이용한 압축에 비해 압축 효율이 낮다. 그리고, 체적소 데이터를 이용할 경우, 이를 스켈레톤화 하여 데이터량을 더욱 줄일 수 있다. 따라서 본 논문에서는 3차원 체 적소 데이터의 규칙성과 스켈레톤을 이용한 압축 기법을 제안할 것이다.

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Three-dimensional Texture Coordinate Coding Using Texture Image Rearrangement (텍스처 영상 재배열을 이용한 삼차원 텍스처 좌표 부호화)

  • Kim, Sung-Yeol;Ho, Yo-Sung
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.43 no.6 s.312
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    • pp.36-45
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    • 2006
  • Three-dimensional (3-D) texture coordinates mean the position information of torture segments that are mapped into polygons in a 3-D mesh model. In order to compress texture coordinates, previous works reused the same linear predictor that had already been employed to code geometry data. However, the previous approaches could not carry out linear prediction efficiently since texture coordinates were discontinuous along a coding order. Especially, discontinuities of texture coordinates became more serious in the 3-D mesh model including a non-atlas texture. In this paper, we propose a new scheme to code 3-D texture coordinates using as a texture image rearrangement. The proposed coding scheme first extracts texture segments from a texture. Then, we rearrange the texture segments consecutively along the coding order, and apply a linear prediction to compress texture coordinates. Since the proposed scheme minimizes discontinuities of texture coordinates, we can improve coding efficiency of texture coordinates. Experiment results show that the proposed scheme outperforms the MPEG-4 3DMC standard in terms of coding efficiency.

Feature-based Topological Mesh Metamorphosis (위상 변환을 통한 특징 기반 메쉬 몰핑)

  • An, Min-Su;Lee, Seung-Yong
    • Journal of the Korea Computer Graphics Society
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    • v.7 no.4
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    • pp.1-8
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    • 2001
  • 3D mesh metamorphosis (morphing) deals with two input polyhedral objects and generates an animation in which the source mesh gradually changes to the target through in-between meshes. The basic and common idea of previous mesh morphing techniques can be summarized as the construction and interpolation of a metamesh. However, an approach based on a metamesh has fundamental limitations of complicated in-between meshes and no topology (connectivity) changes in a metamorphosis. This paper presents a novel approach for 3D mesh morphing, which is not based on a metamesh and overcomes the limitations of previous work. The approach simultaneously interpolates the topology and geometry of input meshes. With the approach, an in-between mesh contains only the vertices from the source and target meshes. Since no additional vertices are introduced, the in-between meshes are much simpler than those generated by previous techniques.

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User-Steered Extraction of Geometric Features for 3D Triangular Meshes (사용자 의도에 의한 삼차원 삼각형 메쉬의 기하적 특징 추출)

  • Yoo, Kwan-Hee;Ha, Jong Sung
    • Journal of the Korea Computer Graphics Society
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    • v.9 no.2
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    • pp.11-18
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    • 2003
  • For extracting geometric features in 3D meshes according to user-steering with effective interactions. this paper generalizes the 2D algorithms of snapping and wrapping that. respectively. moves a cursor to a nearby feature and constructs feature boundaries. First. we define approximate curvatures and move cost functions that are the numerical values measuring the geometric characteristics of the meshes, By exploiting the measuring values. the algorithms of geometric snapping and geometric wrapping are developed and implemented. We also visualize the results from applying the algorithms to extracting geometric features of general 3D mesh models such as a face model and a tooth model.

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Sequential 3D Mesh Coding using Vertex Pedigree based on Wave Partitioning (파동분할 기반의 꼭지점 계보를 이용한 순차적 삼차원 메쉬 부호화)

  • 김태완;안정환;양창모;호요성
    • Proceedings of the Korean Society of Broadcast Engineers Conference
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    • 2001.11b
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    • pp.213-218
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    • 2001
  • 본 논문에서는 파동분할(Wavepartitioning) 방식을 기반으로 꼭지점들간의 특징적인 관계(Vertex Pedigree)를 이용한 순차적(Sequential) 메쉬 부호화 방식을 제안한다. 파동분할 방식은 호수에 물방울이 퍼져 나가는 자연 원리를 이용하여 초기 삼각형의 주위에 삼각형을 덧붙여 가면서 하나의 SPB(Small Processing Block)을 만들어내는 방식이다. 이 방식을 이용하여 하나의 모델을 서로 독립적인 SPB로 분할하고, 각각의 SPB내에서 초기 삼각형을 중심으로 그것에 덧붙여진 삼각형에 의해 만들어진 원 또는 반원을 찾는다. 또한, 그 원주를 따라 순차적으로 꼭지점을 구하면 각각의 꼭지점들은 서로의 관계에 따라 일정한 패턴으로 늘어서게 되고, 이것을 이용하여 연결성 정보 없이 부가 정보만으로 모델을 순차적으로 무손실 부호화한다.

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Greedy Merging Method Based on Weighted Geometric Properties for User-Steered Mesh Segmentation (사용자 의도의 메쉬분할을 위한 기하적 속성 가중치 기반의 그리디 병합 방법)

  • Ha, Jong-Sung;Yoo, Kwan-Hee
    • The Journal of the Korea Contents Association
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    • v.7 no.6
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    • pp.52-59
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    • 2007
  • This paper presents a greedy method for user-steered mesh segmentation, which is based on the merging priority metric defined for representing the geometric properties of meaningful parts. The priority metric is a weighted function composed of five geometric parameters: distribution of Gaussian map, boundary path concavity, boundary path length, cardinality, and segmentation resolution. This scheme can be extended without any modification only by defining more geometric parameters and adding them. Our experimental results show that the shapes of segmented parts can be controlled by setting up the weight values of geometric parameters.

3D Mesh Simplification Using Subdivided Edge Classification (세분화된 에지 분류 방법을 이용한 삼차원 메쉬 단순화)

  • 장은영;호요성
    • Proceedings of the IEEK Conference
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    • 2000.11c
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    • pp.109-112
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    • 2000
  • Many applications in computer graphics require highly detailed complex models. However, the level of detail may vary considerably according to applications. It is often desirable to use approximations in place of excessively detailed models. We have developed a surface simplification algorithm which uses iterative contractions of edges to simplify models and maintains surface error approximations using a quadric metric. In this paper, we present an improved quadric error metric for simplifying meshes. The new metric, based on subdivided edge classification, results in more accurate simplified meshes. We show that a subdivided edge classification captures discontinuities efficiently. The new scheme is demonstrated on a variety of meshes.

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Data Augmentation Method for Deep Learning based Medical Image Segmentation Model (딥러닝 기반의 대퇴골 영역 분할을 위한 훈련 데이터 증강 연구)

  • Choi, Gyujin;Shin, Jooyeon;Kyung, Joohyun;Kyung, Minho;Lee, Yunjin
    • Journal of the Korea Computer Graphics Society
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    • v.25 no.3
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    • pp.123-131
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    • 2019
  • In this study, we modified CT images of femoral head in consideration of anatomically meaningful structure, proposing the method to augment the training data of convolution Neural network for segmentation of femur mesh model. First, the femur mesh model is obtained from the CT image. Then divide the mesh model into meaningful parts by using cluster analysis on geometric characteristic of mesh surface. Finally, transform the segments by using an appropriate mesh deformation algorithm, then create new CT images by warping CT images accordingly. Deep learning models using the data enhancement methods of this study show better image division performance compared to data augmentation methods which have been commonly used, such as geometric conversion or color conversion.