• Title/Summary/Keyword: Triangulation

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Algorithms for Multi-sensor and Multi-primitive Photogrammetric Triangulation

  • Shin, Sung-Woong;Habib, Ayman F.;Ghanma, Mwafag;Kim, Chang-Jae;Kim, Eui-Myoung
    • ETRI Journal
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    • v.29 no.4
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    • pp.411-420
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    • 2007
  • The steady evolution of mapping technology is leading to an increasing availability of multi-sensory geo-spatial datasets, such as data acquired by single-head frame cameras, multi-head frame cameras, line cameras, and light detection and ranging systems, at a reasonable cost. The complementary nature of the data collected by these systems makes their integration to obtain a complete description of the object space. However, such integration is only possible after accurate co-registration of the collected data to a common reference frame. The registration can be carried out reliably through a triangulation procedure which considers the characteristics of the involved data. This paper introduces algorithms for a multi-primitive and multi-sensory triangulation environment, which is geared towards taking advantage of the complementary characteristics of spatial data available from the above mentioned sensors. The triangulation procedure ensures the alignment of involved data to a common reference frame. The devised methodologies are tested and proven efficient through experiments using real multi-sensory data.

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A Band Partitioning Algorithm for Contour Triangulation (등치선 삼각분할을 위한 띠 분할 알고리즘)

  • Choe, Yeong-Gyu;Jo, Tae-Hun
    • The Transactions of the Korea Information Processing Society
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    • v.7 no.3
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    • pp.943-952
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    • 2000
  • The surface reconstruction problem from a set of wire-frame contours is very important in diverse fields such as medical imaging or computer animation. In this paper, surface triangulation method is proposed for solving the problem. Generally, many optimal triangulation techniques suffer from the large computation time but heuristic approaches may produce very unnatural surface when contours are widely different in shape. To compensate the disadvantages of these approaches, we propose a new heuristic triangulation method which iteratively decomposes the surface generation problem from a band (a pair of vertices chain) into tow subproblems from two sub-bands. Generally, conventional greedy heuristic contour triangulation algorithm, suffer from the drastic error propagation during surface modeling when the adjacent contours are different in shape. Our divide-and-conquer algorithm, called band partitioning algorithm, processes eccentric parts of the contours first with more global information. Consequently, the resulting facet model becomes more stable and natural even though the shapes are widely different. An interesting property of our method is hat it supports multi-resolution capability in surface modeling time. According to experiments, it is proved to be very robust and efficient in many applications.

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Extraction variable Level-of-Detail on MultiTriangulation (MultiTriangulation에서의 가변 LOD 추출)

  • 양수정;마상백
    • Proceedings of the Korean Information Science Society Conference
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    • 1999.10b
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    • pp.586-588
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    • 1999
  • 간소화된 메쉬의 다중해상 표현은 실시간으로 원하는 해상 메쉬의 랜더링이 가능하고 저해상 메쉬에서 고해상 메쉬로의 전환이 시각적인 연속성을 갖는다. 또 메쉬의 공간마다 다른 해상도의 표현이 가능하다. 본 논문에서는 기존의 다중해상모델의 특징과 단점을 알아보고 다중모델링 이슈을 제시한다. 효율적인 가변 LOD를 위한 기존의 다중해상 모델을 일반화시킨 MT(MultiTriangulation)를 제시한다. MT의 구조적 특징, MT에서의 선택적 상세화와 시점과의 거리에 따른 가변 LOD 질의를 알아본다.

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SEMIALGEBRAIC G CW COMPLEX STRUCTURE OF SEMIALGEBRAIC G SPACES

  • Park, Dae-Heui;Suh, Dong-Youp
    • Journal of the Korean Mathematical Society
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    • v.35 no.2
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    • pp.371-386
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    • 1998
  • Let G be a compact Lie group and M a semialgebraic G space in some orthogonal representation space of G. We prove that if G is finite then M has an equivariant semialgebraic triangulation. Moreover this triangulation is unique. When G is not finite we show that M has a semialgebraic G CW complex structure, and this structure is unique. As a consequence compact semialgebraic G space has an equivariant simple homotopy type.

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Application of Delaunay Triangulation on RP (Delaunay삼각형 분할법의 RP에의 응용)

  • 명태식;채희창;김옥현
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.8 no.3
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    • pp.35-41
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    • 1999
  • STL which is used in Rapid Prototyping is composed of a lot of triangular facets. The number of triangles and the shapes of these triangles determine the quality of STL. Therefore, proper algorithm is necessary to enhance the quality of triangular patch. In this paper we used the Delaunay triangulation method to apply to following processes. 1) On processing for reducing sharp triangles which cause errors on intersection. 2) On processing for connecting two or more collinear edges. 3) On processing for deleting unnecessarily inserted points in coplanar polygon.

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A Modified Genetic Algorithm for Minimum Weight Triangulation (최소가중치삼각화 문제를 위한 개선된 유전자 알고리듬)

  • Lee, Bum-Joo;Han, Chi-Geun
    • Journal of Korean Institute of Industrial Engineers
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    • v.26 no.3
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    • pp.289-295
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    • 2000
  • The triangulation problem is to make triangles using the given points on the space. The Minimum Weight Triangulation(MWT) is the problem of finding a set of triangles with the minimum weight among possible set of the triangles. In this paper, a modified genetic algorithm(GA) based on an existing genetic algorithm and multispace smoothing technique is proposed. Through the computational results, we can find the tendency that the proposed GA finds good solutions though it needs longer time than the existing GA does as the problem size increases.

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ELEMENTARY DISKS IN TRUNCATED TRIANGULATIONS

  • Kang, Ensil
    • The Pure and Applied Mathematics
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    • v.22 no.1
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    • pp.91-99
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    • 2015
  • A normal surface is determined by how the surface under consideration meets each tetrahedron in a given triangulation. We call such a nice embedded disk, which is a component of the intersection of the surface with a tetrahedron, an elementary disk. We classify all elementary disk types in a truncated ideal triangulation.

Distributed Kinetic Delaunay Triangulation

  • Yoo Taewon;Choi Sunghee;Lee Hyonik;Lee Jinwon
    • Proceedings of the Korean Information Science Society Conference
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    • 2005.11a
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    • pp.964-966
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    • 2005
  • This paper proposes a distributed algorithm to maintain the Delaunay triangulation of moving points. We assume that every point is a processor which can only communicate with the adjacent points connected by edges in the Delaunay triangulation. The topology changes of the Delaunay triangulation due to the movement of the points are updated automatically by local operations of the points without any centralized processor or global information.

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A Study on Transient Chip Formation in Cutting with Self-Propelled Rotary Tools-Experimental Verification (자기추진 로타리 공구를 사용한 절삭에서 천이칩 형성에 관한 연구 - 실험에 의한 증명)

  • 최기흥;최기상;김정수
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.17 no.8
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    • pp.1910-1920
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    • 1993
  • An experimental study to investigate the unconventional chip formation called triangulation of chip in cutting with a SPRT (self-propelled rotary tool) is performed using acoustic emission (AE) signal analysis. In doing that, a quantitative model of the AE RMS signal in triangulation with a SPRT is first developed. The predicted results from this model show good correlation between the AE RMS signal and the general characteristics of triangular chip formation. Then, effects of various process parameters such as cutting conditions (cutting speed, depth of cut, oblique angle and normal rake angle) and the work material properties on the chip formation in cutting with a SPRT are explored. Special attention is paid to the work material properties which are found to have significant effects on triangulation.

Higher Order Elements by Delaunay Triangulation (드로네이기법에 의한 고차 유한요소 생성)

  • 송영준
    • Computational Structural Engineering
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    • v.9 no.4
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    • pp.141-154
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    • 1996
  • Delaunay triangulation is a very powerful method of mesh generation for its versatility such as handling complex geometries, element density control, and local/global remeshing capability, The limit of generating simplex elements(3-node elements in 2-D) only is resolved by adding generation module of 6-node quadratic elements. Since proposed adjacency does not change from 3-node element mesh to 6-node mesh, generation module can utilize the original simplex element generator. Therefore, versatility of the Delaunay triangulation is preserved. A simple upsetting problem is employed to show the possibility of the algorithm.

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