• Title/Summary/Keyword: coplanarity

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Algorithm to Improve Accuracy of Location Estimation for AR Games (AR 게임을 위한 위치추정 정확도 향상 알고리즘)

  • Han, Seo Woo;Suh, Doug Young
    • Journal of Broadcast Engineering
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    • v.24 no.1
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    • pp.32-40
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    • 2019
  • Indoor location estimation studies are needed in various fields. The method of estimating the indoor position can be divided into a method using hardware and a method using no hardware. The use of hardware is more accurate, but has the disadvantage of hardware installation costs. Conversely, the non-hardware method is not costly, but it is less accurate. To estimate the location for AR game, you need to get the solution of the Perspective-N-Point (PnP). To obtain the PnP problem, we need three-dimensional coordinates of the space in which we want to estimate the position and images taken in that space. The position can be estimated through six pairs of two-dimensional coordinates matching the three-dimensional coordinates. To further increase the accuracy of the solution, we proposed the use of an additional non-coplanarity degree to determine which points would increase accuracy. As the non-coplanarity degree increases, the accuracy of the position estimation becomes higher. The advantage of the proposed method is that it can be applied to all existing location estimation methods and that it has higher accuracy than hardware estimation.

Evidence gathering for line based recognition by real plane

  • Lee, Jae-Kyu;Ryu, Moon-Wook;Lee, Jang-Won
    • 한국HCI학회:학술대회논문집
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    • 2008.02a
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    • pp.195-199
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    • 2008
  • We present an approach to detect real plane for line base recognition and pose estimation Given 3D line segments, we set up reference plane for each line pair and measure the normal distance from the end point to the reference plane. And then, normal distances are measured between remains of line endpoints and reference plane to decide whether these lines are coplanar with respect to the reference plane. After we conduct this coplanarity test, we initiate visibility test using z-buffer value to prune out ambiguous planes from reference planes. We applied this algorithm to real images, and the results are found useful for evidence fusion and probabilistic verification to assist the line based recognition as well as 3D pose estimation.

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3D Inspection of Printed Circuit Boards (PCB의 3차원 검사)

  • 조홍주;박현우;이준재
    • Proceedings of the IEEK Conference
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    • 2003.07e
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    • pp.2375-2378
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    • 2003
  • In manufacture of printed circuit boards, one important issue is precisely to measure the three-dimensional shape of the solder paste silk-screened prior to direct surface mounting of chips. This paper presents the 3D shape reconstruction of solder paste using the optical triangulation method based on structured light or slit beam and the measurement algorithm for height, volume. area, and coplanarity on component pads from the 3D range image. Futhermore, statistical process control function is incorporated for process capability analysis.

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Generation of Mini-compacted Thin Film Hybrid Package by Ceramic Ball Grid Array (CBGA를 통한 초소형/박형 박막하이브리드 패키지 구현)

  • 김상희
    • Journal of the Microelectronics and Packaging Society
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    • v.2 no.1
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    • pp.59-68
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    • 1995
  • 박막제조 기술 및 BGA패캐지를 이용하여 Wellcom 2000 system 소요 OCU Board 의 집적화를 구현하였다. 기존 PCB에 실장되는 소자 일부를 2 Channel BGA 패캐지로 모 듈화한 결과 약 1/6로 소형화시킬수 있었으며 8 Channel의 모율화는 현재 진행중인 다층 구조의 제조 기술 개발과 아울러 BGA 패캐지로 실현이 가능하며 1/10로집접화할수 있음을 알수 있었다. 또한 PCB위에 Bare Chip을 실장하여 Wire Bonding 한 COB를 구현하여 CBGGA의 PCB실장과 함께한 모듈을 형성해 보았다. CBGA패캐지에 Ball Shear Test, In Circuit Test 온도 환경주기시험(TCT) 진동시험을 통하여 신뢰성을 입증하였다. 이때 CBGA의 Coplanarity(3.2%) 증진을 위하여 Ceramic Pad에 선택적인 도금 방식을 개발적용 하였다.

Synthesis and Electrical Conductivities of Poly(1,4-phenylenevinylene-co-2,3,5,6-tetramethyl-1,4-phenylenevinylene)s

  • Jin, Jung-Il;Kang, Heung-Joong;Shim, Hong-Ku
    • Bulletin of the Korean Chemical Society
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    • v.11 no.5
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    • pp.415-420
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    • 1990
  • A series of copolymers of poly(1,4-phenylenevinylene-co-2,3,5,6-tetramethyl- 1,4-phenylenevinylene), poly(PV-co-TMPV), were prepared in film forms from the precursor polymer films. The sulfonium salt precursor polymers were synthesized by copolymerization of the mixtures of the respective bis(sulfonium salt) monomers. All of the copolymer films could be doped with $FeCl_3$ to have high electrical conductivities and they showed good air stability. The maximum conductivity of the $FeCl_3$-doped films ranged $10^{-3}\;to\;10^2Scm^{-1}$ depending on the composition of the copolymer films. However, these copolymer films could not be doped with iodine. The coplanarity of PV and TMPV units in the main chain appears to be affected by steric effect of the methyl groups in the TMPV units.

Quantum Chemical Designing of Efficient Sensitizers for Dye Sensitized Solar Cells

  • Abdullah, Muhammad Imran;Janjua, Muhammad Ramzan Saeed Ashraf;Mahmood, Asif;Ali, Sajid;Ali, Muhammad
    • Bulletin of the Korean Chemical Society
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    • v.34 no.7
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    • pp.2093-2098
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    • 2013
  • Density functional theory (DFT) was used to determine the ground state geometries of indigo and new design dyes (IM-Dye-1 IM-Dye-2 and IM-Dye-3). The time dependant density functional theory (TDDFT) was used to calculate the excitation energies. All the calculations were performed in both gas and solvent phase. The LUMO energies of all the dyes were above the conduction band of $TiO_2$, while the HOMOs were below the redox couple (except IM-Dye-3). The HOMO-LUMO energy gaps of new design dyes were smaller as compared to indigo. All new design dyes were strongly red shifted as compared to indigo. The improved light harvesting efficiency (LHE) and free energy change of electron injection ${\Delta}G^{inject}$ of new designed sensitizers revealed that these materials would be excellent sensitizers. The broken coplanarity between the benzene near anchoring group having LUMO and the last benzene attached to TPA unit in all new design dyes consequently would hamper the recombination reaction. This theoretical designing will the pave way for experimentalists to synthesize the efficient sensitizers for solar cells.

The Technique Development for 3D Deformation Analysis of Railroad Bridge Using the Non-metric Camera (비측정용 디지털 카메라를 이용한 철도교량의 3차원 변형해석 기법개발)

  • Lee, Hyo-Seong;Ahn, Ki-Weon;Park, Byung-Uk;Shin, Seok-Hyo
    • Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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    • 2010.04a
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    • pp.129-131
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    • 2010
  • This study is to measure 3d deformation of railroad-bridge of steel structure using the non-metric high-resolution digital camera. Measuring the deformation is to be utilized relative orientation using the coplanarity for reduction of the field survey and efficiency of the work. The results are compared with deformation by exterior orientation parameters, which are computed from 3d measurement of control points by the Total-station. Then accuracy of the utilized method will be verified.

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"MODEL SPELL CHECKER" FOR PRIMITIVE-BASED AS-BUILT MODELING IN CONSTRUCTION

  • Kwon Soon-Wook;Frederic Bosche;Huh Youngki
    • Korean Journal of Construction Engineering and Management
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    • v.5 no.5 s.21
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    • pp.163-171
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    • 2004
  • This research investigates a Modeling Spell Checker that, similarly to Word Spell Checker for word processing software, would conform as-built 3D models to standard construction rules. The work is focused on the study of pipe-spools. Specifically pipe diameters and coplanarity are checked and corrected by the Modeling Spell Checker, and elbows are deduced and modeled to complete models. Experiments have been conducted by scanning scenes of increasing levels of complexity regarding the number of pipes, the types of elbows and the number of planes constituting pipe-spools. For building models of pipes from sensed data, a modeling method, developed at the University of Texas at Austin, that is based on the acquisition of sparse point clouds and the human ability to recognize geometric shapes has been used Results show that primitive-based models obtained after scanning construction sites can be corrected and even improved automatically, and, since such models are expected to be used as feedback control models for equipment operators, the higher modeling accuracy achieved with the Modeling Spell Checker could potentially increase the level of safety in construction. Result also show that some improvements are still needed especially regarding the co-planarity of pipes. In addition, results show that the modeling accuracy significantly depends on the primitive modeling method, and improvement of that method would positively impact the modeling spell checker.