• Title/Summary/Keyword: Scattered points

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Multiscale Implicit Functions for Unified Data Representation

  • Yun, Seong-Min;Park, Sang-Hun
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.5 no.12
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    • pp.2374-2391
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    • 2011
  • A variety of reconstruction methods has been developed to convert a set of scattered points generated from real models into explicit forms, such as polygonal meshes, parametric or implicit surfaces. In this paper, we present a method to construct multi-scale implicit surfaces from scattered points using multiscale kernels based on kernel and multi-resolution analysis theories. Our approach differs from other methods in that multi-scale reconstruction can be done without additional manipulation on input data, calculated functions support level of detail representation, and it can be naturally expanded for n-dimensional data. The method also works well with point-sets that are noisy or not uniformly distributed. We show features and performances of the proposed method via experimental results for various data sets.

A Study of a Surface Modeling Interpolating a Polygonal Curve Net Constructed from Scattered Points (점군으로부터 형성된 다각곡선망을 보간하는 곡면모델링에 관한 연구)

  • Ju, Sang-Yoon;Jun, Cha-Soo
    • Journal of Korean Institute of Industrial Engineers
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    • v.21 no.4
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    • pp.529-540
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    • 1995
  • The paper deals with a procedure for constructing a composite surface interpolating a polygonal curve mesh defined from 3D scattered points. The procedure consists of a poly-angulation, construction of a curve net, and interpolation of the curve net. The poly-angulation contains a stage that changes a triangular edge net obtained from a triangulation into a poly-angular edge net. A curve net is constructed by replacing edges on the edge net with cubic Bezier curves. Finally, inside of an n-sided polygon is interpolated by n subdivided triangular subpatches. The method interpolates given point data with relatively few triangular subpatches. For an n-sided polygon, our method constructs an interpolant with n subdivided triangular subpatches while the existing triangular surface modeling needs 3(n-2) subpatches. The obtained surface is composed of quartic triangular patches which are $G^1$-continuous to adjacent patches.

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A SURFACE RECONSTRUCTION METHOD FOR SCATTERED POINTS ON PARALLEL CROSS SECTIONS

  • Kim, Phil-Su
    • Journal of the Korean Society for Industrial and Applied Mathematics
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    • v.9 no.2
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    • pp.29-43
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    • 2005
  • We consider a surface reconstruction problem from geometrical points (i.e., points given without any order) distributed on a series of smooth parallel cross sections in ${\mathbb{R}}^3$. To solve the problem, we utilize the natural points ordering method in ${\mathbb{R}}^2$, described in [18], which is a method of reconstructing a curve from a set of sample points and is based on the concept of diffusion motions of a small object from one point to the other point. With only the information of the positions of these geometrical points, we construct an acceptable surface consisting of triangular facets using a heuristic algorithm to link a pair of parallel cross-sections constructed via the natural points ordering method. We show numerical simulations for the proposed algorithm with some sets of sample points.

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A Implementation of Surveyed Control Point Management System for National Land based on RFID (RFID 기반의 국토측량 기준점 관리 시스템 구현)

  • Cho, Jong Sik;Kim, Young Gon;Lee, Young Woong;Ju, Jong Gil;Seo, Ho Suk;Sim, Choon Bo;Sin, Chang Sun
    • Journal of Korea Society of Digital Industry and Information Management
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    • v.6 no.1
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    • pp.13-22
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    • 2010
  • In this paper, we propose a management system for positioning and indicating the surveyed control point using RFID and UMPC. This system is composed of digital control point, management system and application. The digital control point transmits information of the surveyed control point and the management system receives the data from the digital control points and manages the scattered digital control points. The system offers three services for managing the surveyed control point. The first service is control point monitoring service for identifying the change of location, locating the missing control point and the second service is control point search service notifying selected control point to user, and the third service is control point land management service for editing the control point information in the land. Therefore, this system makes it easy for administrators to access the control point information of the scattered surveyed control point through the country and enhances the managing efficiency.

The Fast 3D mesh generation method for a large scale of point data (대단위 점 데이터를 위한 빠른 삼차원 삼각망 생성방법)

  • Lee, Sang-Han;Park, Kang
    • Proceedings of the KSME Conference
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    • 2000.11a
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    • pp.705-711
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    • 2000
  • This paper presents a fast 3D mesh generation method using a surface based method with a stitching algorithm. This method uses the surface based method since the volume based method that uses 3D Delaunay triangulation can hardly deal with a large scale of scanned points. To reduce the processing time, this method also uses a stitching algorithm: after dividing the whole point data into several sections and performing mesh generation on individual sections, the meshes from several sections are stitched into one mesh. Stitching method prevents the surface based method from increasing the processing time exponentially as the number of the points increases. This method works well with different types of scanned points: a scattered type points from a conventional 3D scanner and a cross-sectional type from CT or MRI.

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Domain Selection Using Asymptotic Decider Criterion in Volume Modeling Based on Tetrahedrization (사면체 기반의 볼륨 모델링에서 점근선 판정기를 이용한 영역의 선택)

  • Lee, Kun;Gwun, Ou-Bong
    • The KIPS Transactions:PartA
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    • v.10A no.1
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    • pp.59-68
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    • 2003
  • 3-D data modeling of a volumetric scattered data is highly demanded for geological structure inspection, environment visualization and supersonic testing. The data used in these area are generally irregularly scattered in a volume data space, which are much different from the structured points data (cuberille data) used in Marching cube algorithm. In this paper, first we explore a volume modeling method for the scattered data based on tetrahedral domain. Next we propose a method for solving the ambiguity of tetrahedral domain decision using asymptotic decider criterion. Last we implement a simple visualization system based on the proposed asymptotic decider criterion and compare it with a system based on sphere criterion. In deciding tetrahedral domain, sphere criterion considers only positional values but asymptotic decider criterion considers not only positional values but also functional values, so asymptotic decider criterion is more accurate on deciding tetrahedral domain than sphere criterion.

Effects of the Scattered Radiation on Image Quality and Exposure Dose in Chest Radiography (흉부X선촬영시(胸部X線撮影時) 산란선(散亂線)이 화질(畵質)과 피폭선량(被曝線量)에 미치는 영향(影響))

  • Iino, Yu;Hayashi, Taro;Ishida, Yuji;Maeda, Mika;Sakurai, Tatsua;Lee, Man-Koo;An, Bong-Sun;Kim, Jung-Min
    • Journal of radiological science and technology
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    • v.16 no.2
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    • pp.27-38
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    • 1993
  • To investigate relationships between image guality and exposure dose, Chest X-ray films were evaluated for the following points:how much scattered radiation can affect reduction in image quality and can be permissible diagnostically? For this purpose using a test charts and Burger's phantoms. The visual evaluation of their X-ray films and the measurements of scattered radiation were carried out. The dose of scattered radiation ranging from 20 to 25% was found to be for nothing in any diagnostic obstacle. In this range, surface doses were low of 17, 21, and $25{\mu}Gy$ for The thickness of the chest of 15, 20 and 25 cm respectively. Comparison of these high voltage X-ray films with low voltage ones showed a surface dose rate of 1:11.7. Therefore, X-ray quality, photosensitive materials(film and screen) and grid should be selected very carefully for the purpose of reduction in exposure dose.

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A Study on the Use of the Standard Plans and Housing Satisfaction Level of the Recently Constructed Rural Houses (신축 농촌주택의 표준설계도 이용과 주거만족도 -충북 옥천군 군북면과 충남 예산군 고덕면을 중심으로-)

  • Park, Kyoungok
    • Journal of the Korean Institute of Rural Architecture
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    • v.1 no.3
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    • pp.27-34
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    • 1999
  • The purpose of this study was to provide basic information on the rural house planning through the research on the use of the standard plans, architectural characteristics, importance of the planning points and housing satisfaction of the residents. 25 rural households scattered around Chungchong provinces-south and north- were surveyed for this study through the questionnaire method. The results of this study were as follows. The importance considered first was the low construction costs, and therefore the standard plans were not fully acknowledged and commonly used. Most real plans are the single-floor houses with 3 rooms, having 25-30 pyong magnitude. The planning points stressed highly were the storage space, convenience of the plan and size of the living room. Housing satisfaction level was high on direction of the facade, size of the living room and position of the bath/washing room, but low for the storage space.

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An Accelerated Simulated Annealing Method for B-spline Curve Fitting to Strip-shaped Scattered Points

  • Javidrad, Farhad
    • International Journal of CAD/CAM
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    • v.12 no.1
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    • pp.9-19
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    • 2012
  • Generation of optimum planar B-spline curve in terms of minimum deviation and required fairness to approximate a target shape defined by a strip-shaped unorganized 2D point cloud is studied. It is proposed to use the location of control points as variables within the geometric optimization framework of point distance minimization. An adaptive simulated annealing heuristic optimization algorithm is developed to iteratively update an initial approximate curve towards the target shape. The new implementation comprises an adaptive cooling procedure in which the temperature change is adaptively dependent on the objective function evolution. It is shown that the proposed method results in an improved convergence speed when compared to the standard simulated annealing method. A couple of examples are included to show the applicability of the proposed method in the surface model reconstruction directly from point cloud data.