• Title/Summary/Keyword: shadow moire

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A Study on Mapping using Projection Moir Technique (투영 모아레 기법을 이용한 Mapping에 관한 연구)

  • 유복모;이성옥;유광호
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.3 no.2
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    • pp.1-10
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    • 1985
  • Moire technique is generally divided into shadow Moire Technique and Projection Moire Technique. In this paper, determinating the direction of reference planes for this system, by comparing the results of this system with those of general terrestrial photogrammetry, is an objective of this paper. For the objective, control surveying is done and the results of control surveying are compared with those of moire photograph. In this technique, it is found that though the positions of a projector and a reference grid are not moved, a desired moire contour whose the reference plane is different respectively is easily obtained by changing the pitches of a master grid and a reference grid on an object. Also it is found that when the pitches of the two grids on an object are equal, a moire contour which has the reference plane parallel to the object can be obtained.

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A Scheme of User Face Recognition using a Moire Phenomenon in IoT Environment (IoT환경에서 무아레 현상을 이용한 사용자 얼굴 인증 기법)

  • Cho, Ik-Hyun;Lee, Keun-Ho
    • Journal of Digital Convergence
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    • v.17 no.2
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    • pp.171-176
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    • 2019
  • In modern times, many IoT products are being used as all things and devices are connected to the Internet and IoT products become easily accessible through the network. For the convenience of users, IoT products can be remotely operated automatically without manual operation. Various research and development are underway to improve the convenience of users by using IoT products. However, since only the convenience of the users is pursued, in terms of security, there is a serious problem that exposes the user's personal information. This paper has proposed a method to apply $moir{\acute{e}}$ technology to IoT products in order to improve the performance of security, and a method to increase the safety of IoT products using user face authentication based on shadow $moir{\acute{e}}$ as a $moir{\acute{e}}$ phenomenon method, and the projection $moir{\acute{e}}$. When comparing the existing IoT products and IoT products applied with $moir{\acute{e}}$ technology, IoT products applied with $moir{\acute{e}}$ technology are safer in terms of security.

Weighted least-square phase-unwrapping method using intensity modulation in moire interferometry (모아레 간섭계에서 Modulation을 이용한 가중 최소자승 위상 복원 방법에 관한 연구)

  • 이현호;채규민;박승한
    • Proceedings of the Optical Society of Korea Conference
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    • 2000.08a
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    • pp.128-129
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    • 2000
  • 3차원 형상측정에서 많이 쓰이고 있는 모아레 간섭계에는 그 setup에 따라 Projection Type과 Shadow Type이 있다. 이러한 모아레 간섭계는 광원과 측정 카메라의 각도에 의해 물체의 형상을 측정하게 된다. 그러나, 이러한 광원과 측정 카메라의 각도에 의해 생겨나는 그림자에 의한 영향 때문에 물체의 형상이 굴곡이 심한 곳은 측정하기 어렵다. 본 논문에서는 아래 그림과 같이 두 개 이상의 광원을 사용하여 그 영향을 줄이기 위한 방법을 제안하였다. 이 방법은 projection type이나 shadow type에서 동일하게 적용 가능할 것으로 예상된다. (중략)

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Experimental Analysis of Stress Intensity Factors by Combination With Moire Method and Slab Analogy (모아레法 과 스라브相似 의 複合 에 의한 應力擴大係數 의 實驗的 解析法 -有限板크랙 의 $K_I$$K_II$-)

  • 최선호;권재도;김종주;채영석
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.6 no.4
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    • pp.315-322
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    • 1982
  • The slab analogy method was introduced in the 1920's for the first time as a new experimental stress analysis method. Notwithstanding its theoretical propriety, this method has not been recognized as efficient one because of its difficulty in practical measurement of the slab curvature. In this paper, aiming at experimental determination of two-dimensional stress intensity factors(S. I. F) of arbitrarily shaped cracks which had been regarded as almost impossible by conventional method, the slab analogy was reevaluated. Measuring of slab curvature was replaced by three simple measuring factors to overcome vital slab-analogy's shortcoming by joint use of the shadow-moire method. A determination formula was also derived from the theory of fracture mechanics. By this newly exploited method, it was found that the slab analogy still has its great advantage in determination of S.I.F. of arbitrarily shaped cracks with considerable accuracy compared with existent experimental methods.

The measurement for micro shape by Phase Shift method I (단파장 위상천이를 이용한 미세형상 측정 I)

  • Park Youn-chang;Kim Ho-yul
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2005.05a
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    • pp.335-341
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    • 2005
  • The development of Shadow Moire in many kinds of methods for acquiring 3-dimensional information from an object is written in this paper. The fringe is appeared, when a grating mask makes its shadow on the object. The object is moved along x-axis more then 3 times to get phases from its fringe that contains data of the object's height. PMP{Phase Measuring Profilometry) is used for analyzing these images from a CCD camera. The calculated phase is remedied for expending the restricted results due to range of the $tan^{-1}$.

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밀링가공에서 이미지 프로세싱을 이용한 다인공구의 파손검출기법 개발(ㅣ)

  • 사승윤;최영규;김영일;홍윤석;유봉환
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1993.04b
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    • pp.92-96
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    • 1993
  • Modern NC machine tools require a more and more exact monitoring and control of cutting process. A very important parameter is tool wear used to optimize cutting data and to change tools at the right time. In this study, a real-time multi-tool fracture method is proposed for measuring crater from fringe patterns generated by uni-shadow-moire. An optical technique using laser for non-contact measurement of tool fracture is presented. The technology in which the tool is illuminated by a beam of He-Ne laser and then the image of tool fracture CCD camera.

Buckling and Postbuckling Behavior of Stiffened Laminated Composite Panels (보강된 복합적층 판넬의 좌굴 및 좌굴후 거동 연구)

  • Lee, In-Cheol;Gyeong, U-Min;Gong, Cheol-Won;Hong, Chang-Seon;Kim, Cheon-Gon
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.20 no.10
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    • pp.3199-3210
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    • 1996
  • The buckling and postbuckling behaviors were sutdied analytically and experimentally for stiffened laminated composite panels under compression loading. The panels with I-, blade, -and hat-shapeed stiffeners were investigated. In the analysis, the stiffened panels were anlyzed using the nonlinear finite element method combined with an improved arc-length method. The progressive failure analysis was done by adopting the maximum stress criterion and complete unloading failure model. The effects of the fiber angles were investigated on the buckling and postbuckling behaviors. In the experiment, the web and the lower cap of each stiffener were formed by the continuous lay-up of the skin for cocuring the stiffened panels. Therefore, the separation between stiffener and skin was not found in the junction part even after postbuckling ultimate load and the stiffened panels had excellent postbuckling load carrying capacity. A shadow moire thchnique was used to monitor the out-of-plane deformations of the panels. The piezoelectric films were attached to the panels to get the failure characteristics of the panel. The analytical results on the buckling load, postbuckling ultimate load, and failure pattern showed good agreement with the experimental results.