• Title, Summary, Keyword: coplanar points

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A Study On the Comparison of the Geometric Invariance From A Single-View Image (단일 시각방향 영상에서의 기하 불변량의 특성 비교에 관한 연구)

  • 이영재;박영태
    • Proceedings of the IEEK Conference
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    • pp.639-642
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    • 1999
  • There exist geometrically invariant relations in single-view images under a specific geometrical structure. This invariance may be utilized for 3D object recognition. Two types of invariants are compared in terms of the robustness to the variation of the feature points. Deviation of the invariant relations are measured by adding random noise to the feature point location. Zhu’s invariant requires six points on adjacent planes having two sets of four coplanar points, whereas the Kaist method requires four coplanar points and two non-coplanar points. Experimental results show that the latter method has the advantage in choosing feature points while suffering from weak robustness to the noise.

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Precise Detection of Coplanar Checkerboard Corner Points for Stereo Camera Calibration Using a Single Frame (스테레오 카메라 캘리브레이션을 위한 동일평면 체커보드 코너점 정밀검출)

  • Park, Jeong-Min;Lee, Jong-In;Cho, Joon-Bum;Lee, Joon-Woong
    • Journal of Institute of Control, Robotics and Systems
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    • v.21 no.7
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    • pp.602-608
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    • 2015
  • This paper proposes an algorithm for precise detection of corner points on a coplanar checkerboard in order to perform stereo camera calibration using a single frame. Considering the conditions of automobile production lines where a stereo camera is attached to the windshield of a vehicle, this research focuses on a coplanar calibration methodology. To obtain the accurate values of the stereo camera parameters using the calibration methodology, precise localization of a large number of feature points on a calibration target image should be ensured. To realize this demand, the idea with respect to a checkerboard pattern design and the use of a Homography matrix are provided. The calibration result obtained by the proposed method is also verified by comparing the depth information from stereo matching and a laser scanner.

Boundary element characterization of coplanar waveguide discontinuities by quasi-static approximation (Quasi-static 근사에 의한 코플래너 도파로 불연속의 경계요소 해석)

  • 강연덕;이택경
    • Journal of the Korean Institute of Telematics and Electronics D
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    • v.34D no.6
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    • pp.1-10
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    • 1997
  • By using the boundary element method, the cahracterization and the circuit modelling of the coplanar waveguide (CPW) discontinuities are performed bvia quasi-static approximation. The capacitive equivalent circuits are obtained by developing the 3-D boundary element method with collocation method. On the triangular patch, the numerical scheme employed the linear basis functions and the analytic solutions of the integrals on the singular points. The capacitive discontinuities of gaps, end-gaps, and open-ends are characterized and the results compared with the conductor backed coplanar waveguides.

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Registration of Multiple CT Images Using Principal Axis-based Rigid Body Transformation (주축기반 강체변환을 이용한 다중 CT 영상의 정합)

  • 유선국;김용욱;이혜연;김희중;김기덕;김남현
    • The Transactions of the Korean Institute of Electrical Engineers D
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    • v.52 no.8
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    • pp.500-505
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    • 2003
  • In this paper, the method to register multiple sets of skull CT images to absolute coordinate system is proposed. Contrary to correspondence paired mapping of previous techniques, four anatomical landmark points, three coplanar points and one non-coplanar point, compose three principal axes simple and unique for efficient registration by means of rigid body transformation. Throughout the numerical simulation with added random noises, the error performances in terms of different rotation and rounding-off of landmark points, and incorrect localization of anatomical landmark and target points are quantitatively analyzed to generalize the proposed technique. Experiments using real skull CT images demonstrate the feasibility for an efficient use in clinical practice.

3-D Pose Estimation of an Elliptic Object Using Two Coplanar Points (두 개의 공면점을 활용한 타원물체의 3차원 위치 및 자세 추정)

  • Kim, Heon-Hui;Park, Kwang-Hyun;Ha, Yun-Su
    • Journal of the Institute of Electronics Engineers of Korea SC
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    • v.49 no.4
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    • pp.23-35
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    • 2012
  • This paper presents a 3-D pose (position and orientation) estimation method for an elliptic object in 3-D space. It is difficult to resolve the problem of determining 3-D pose parameters with respect to an elliptic feature in 3-D space by interpretation of its projected feature onto an image plane. As an alternative, we propose a two points-based pose estimation algorithm to seek the 3-D information of an elliptic feature. The proposed algorithm determines a homogeneous transformation uniquely for a given correspondence set of an ellipse and two coplanar points that are defined on model and image plane, respectively. For each plane, two triangular features are extracted from an ellipse and two points based on the polarity in 2-D projection space. A planar homography is first estimated by the triangular feature correspondences, then decomposed into 3-D pose parameters. The proposed method is evaluated through a series of experiments for analyzing the errors of 3-D pose estimation and the sensitivity with respect to point locations.

Design of Loop Antenna Using Coplanar Waveguide Feeding Method (동일면 도파관 급전방식을 이용한 루프안테나 설계)

  • Yeo, Junho;Lee, Jong-Ig
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • pp.55-56
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    • 2017
  • In this paper, a wideband loop antenna is designed using a CPW feeding method for indoor digital TV applications. The proposed loop antenna consists of a square loop and two circular sectors which connect the loop with central feed points, and the CPW feed line is inserted in the lower circular sector. The CPW feed line is designed to match with the 75 ohm port impedance for DTV applications, and the ground slots are etched in order to improve the impedance matching in the middle frequency region. The optimized antenna is fabricated on FR4 substrate, and the experiment results show that it operates in the frequency band of 463-1,280 MHz for a VSWR < 2, which assures the operation in the DTV band.

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Analysis of Electrostatic Field and Potential Distributions in Conductor-Backed Coupled Coplanar Waveguide Using Conformal Mapping Method (등각사상방법을 이용한 도체로 보강된 결합 도파 선로의 정전기장과 전위 분포 해석)

  • Yoo, Tae-Hoon;Han, Ki-Soo
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.24 no.6
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    • pp.35-42
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    • 2010
  • We use conformal mapping method to derive the analytical expressions for calculating electrostatic fields and electric potentials surrounding the conductor-backed coupled coplanar waveguide(CBCCPW) structure. Using the derived expressions, the electrostatic fields and potentials are computed at various points of the CBCCPW's geometry and the field and potential distributions are analyzed. The proposed method provides a faster and simpler calculation of the field distributions than the full-wave analysis method because no iterations are required. This method can be widely applied to the analysis of microwave integrated circuits using coupled line, such as coupler, filter, and microstrip antenna.

Building Roof Reconstruction in Remote Sensing Image using Line Segment Extraction and Grouping (선소의 추출과 그룹화를 이용한 원격탐사영상에서 건물 지붕의 복원)

  • 예철수;전승헌;이호영;이쾌희
    • Korean Journal of Remote Sensing
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    • v.19 no.2
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    • pp.159-169
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    • 2003
  • This paper presents a method for automatic 3-d building reconstruction using high resolution aerial imagery. First, by using edge preserving filtering, noise is eliminated and then images are segmented by watershed algorithm, which preserves location of edge pixels. To extract line segments between control points from boundary of each region, we calculate curvature of each pixel on the boundary and then find the control points. Line segment linking is performed according to direction and length of line segments and the location of line segments is adjusted using gradient magnitudes of all pixels of the line segment. Coplanar grouping and pplygonal patch formation are performed per region by selecting 3-d line segments that are matched using epipolar geometry and flight information. The algorithm has been applied to high resolution aerial images and the results show accurate 3D building reconstruction.

Camera Calibration for Machine Vision Based Autonomous Vehicles (머신비젼 기반의 자율주행 차량을 위한 카메라 교정)

  • Lee, Mun-Gyu;An, Taek-Jin
    • Journal of Institute of Control, Robotics and Systems
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    • v.8 no.9
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    • pp.803-811
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    • 2002
  • Machine vision systems are usually used to identify traffic lanes and then determine the steering angle of an autonomous vehicle in real time. The steering angle is calculated using a geometric model of various parameters including the orientation, position, and hardware specification of a camera in the machine vision system. To find the accurate values of the parameters, camera calibration is required. This paper presents a new camera-calibration algorithm using known traffic lane features, line thickness and lane width. The camera parameters considered are divided into two groups: Group I (the camera orientation, the uncertainty image scale factor, and the focal length) and Group II(the camera position). First, six control points are extracted from an image of two traffic lines and then eight nonlinear equations are generated based on the points. The least square method is used to find the estimates for the Group I parameters. Finally, values of the Group II parameters are determined using point correspondences between the image and its corresponding real world. Experimental results prove the feasibility of the proposed algorithm.

The Application of Delaunay Triangulation on RP (Delaunay 삼각형 분합법의 RP에의 응용)

  • 김대원
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • pp.129-134
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    • 1998
  • 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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