• Journal of the Institute of Electronics Engineers of Korea SP
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• v.44 no.2 s.314
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• pp.55-62
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• 2007

This paper proposes method to get exquisite third dimension data removing included noise by error that occur in third dimension reconstruction through camera auto-calibration. Though reconstructing third dimension data by previous noise removing method, mesh that area is wide is happened problem by noise. Because mesh's area is important, the proposed algorithm need preprocessing that remove unnecessary triangle meshes of acquired third dimension data. The research analyzes the characteristics of noise using the area information of 3-dimensional meshes, separates a peek noise and a Gauss noise by its characteristics and removes the noise effectively. We give a quantitative evaluation of the proposed preprocessing filter and compare with the mesh smoothing procedures. We demonstrate that our effective preprocessing filter outperform the mesh smoothing procedures in terms of accuracy and resistance to over-smoothing.

• Korean Journal of Computational Design and Engineering
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• v.11 no.2
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• pp.107-114
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• 2006

A new quadrilateral mesh generation technique from an existing triangle mesh is proposed in this paper. The proposed method is based on advancing front method and zero-thickness layer. Beginning with an initial triangular mesh, boundary triangular elements are removed and quadrilateral elements with zero thickness are generated. A quality of quadrilateral elements is improved during a mesh smoothing process. Until all initial triangular elements are removed, this procedure is repeated. Sample meshes are constructed to demonstrate the mesh generation capability of proposed algorithm.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.48 no.4
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• pp.174-181
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• 1999

To obtain more accurate result in the finite element analysis for electric machinery, it is important to have a mesh being of good quality. This paper describes a new technique of mesh generation for the finite element method. When the list of points defining the region of analysis is given, an appropriate distribution of interior points is generated first. Secondly the points are connected to from the trianlges. Finally the connectivity data are used to reposition the interior points using Laplacian smoothing and mesh relaxation technique. In this paper, a mesh searching technique of Lawson which modifies the start mesh is proposed in addition to the above three steps. This algorithm is simple and produces the meshes being of good quality with high speed in comparison with the existing one.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2004.10a
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• pp.75-78
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• 2004

A mesh generation algorithm adapted to the mesh density map using the Delaunay mesh generation technique is developed. In the finite element analyses of the forging processes, the numerical error increases as the process goes on because of discrete property of the finite elements or severe distortion of elements. Especially, in the region where stresses and strains are concentrated, the numerical discretization error will be highly increased. However, it is too time consuming to use a uniformly fine mesh in the whole domain to reduce the expected numerical error. Therefore, it is necessary to construct locally refined mesh at the region where the error is concentrated such as at the die corner. In this study, the point insertion algorithm is used and the mesh size is controlled by moving nodes to optimized positions according to a mesh density map constructed with a posteriori error estimation. An optimization technique is adopted to obtain a good position of nodes. And optimized smoothing techniques are also adopted to have smooth distribution of the mesh and improve the mesh element quality.

• Journal of Korea Multimedia Society
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• v.12 no.4
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• pp.473-482
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• 2009

Reconstructed 3D data from computer vision includes necessarily a noise or an error. When these data goes through a mesh process, the different 3D mesh data from original shape comes to make by a noise or an error. This paper proposed the method that smooths a noise effectively by noise analysis in reconstructed 3D data. Because the proposed method is smooths a noise using the area ratio of the mesh, the pre-processing of unusable mesh is necessary in 3D mesh data. This study detects a peak noise and Gaussian noise using the ratio of 3D volume and 2D area of mesh and smooths the noise with respect of its characteristics. The experimental results using synthetic and real data demonstrated the efficacy and performance of proposed algorithm.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.25 no.6
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• pp.853-859
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• 2001

This paper describes the extended topological clean up procedures to improve the quality of unstructured triangular meshes. As a postprocessing step, topological improvement procedures are applied both for elements that are interior to the mesh and for elements connected to the boundary and then Laplacian-like smoothing is used by default. Previous clean up algorithms are limited to eliminate the nodes of degree 3,4,8,9,10 and pairs of nodes of degree 5. In this study, new clean up algorithms which minimize the triple connection structures combined with degree 5 and 7 (ie ; 5-7-5, 7-7-5, 7-5-7 etc) are added. The suggested algorithms are applied to two example meshes to demonstrate the effectiveness of the approach in improving element quality in a finite element mesh.

• Korean Journal of Computational Design and Engineering
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• v.10 no.1
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• pp.70-75
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• 2005

A 3D solid element mesh generation algorithm was newly developed. 3D surface points of global rectangular coordinates were supplied by a 3D laser scanner. The algorithm is strait forward and simple but it generates mixed solid elements such as hexagonal, pyramid and prism types. Then, the surface triangular or rectangular elements were generated from the solid elements. The key of the algorithm is elimination of elements and 3D adaptive surface smoothing using given 3D surface point data.

• Journal of Mechanical Science and Technology
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• v.18 no.3
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• pp.460-470
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• 2004

A computational analysis of engineering problems with moving domain or/and boundary according to either Lagrangian or Eulerian approach may encounter inherent numerical difficulties, the extreme mesh distortion in the former and the material boundary indistinctness in the latter. In order to overcome such defects in classical numerical approaches, the ALE(arbitrary Lagrangian Eulerian) method is widely being adopted in which the finite element mesh moves with arbitrary velocity. This paper is concerned with the ALE finite element formulation, aiming at the dynamic response analysis of baffled fuel-storage container in yawing motion, for which the coupled time integration scheme, the remeshing and smoothing algorithm and the mesh velocity determination are addressed. Numerical simulation illustrating theoretical works is also presented.

• Journal of computational fluids engineering
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• v.16 no.1
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• pp.30-35
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• 2011

In this paper, our effort to apply 3-D Virtual Reality system for stereoscopic visualization of mesh data on the web is briefly described. This study is an extension of our previous and on-going research efforts to develop an automatic grid generation program specialized for wing mesh, named as eGWing. The program is developed by using JAVA programming language, and it can be used either as an application program on a local computer or as an applet in the network environment. In this research advancing layer method(ALM) augmented by elliptic smoothing method is used for the structured grid generation. And to achieve a stereoscopic viewing capability, two graphic windows are used to render its own viewing image for the left and right eye respectively. These two windows are merged into one image using 3D monitor and the viewers can see the mesh data visualization results with stereoscopic depth effects by using polarizing glasses. In this paper three dimensional mesh data visualization with stereoscopic technique combined with 3D monitor is demonstrated, and the current achievement would be a good start-up for further development of low-cost high-quality stereoscopic mesh data visualization system which can be shared by many users through the web.

• Journal of the Korea Computer Graphics Society
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• v.26 no.3
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• pp.39-48
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• 2020

In this paper, we propose a new technique for filling holes in triangular mesh. First, arbitrary shaped holes are detected. Second, source and target hole patches are generated through triangulation, refinement, fairing, and smoothing. Finally, the shape difference between the two patches is analyzed and a patch with enhanced features is obtained through blending between patches. The effectiveness of the proposed technique is demonstrated by applying the hole filling technique to the triangular mesh model with various shaped holes.