• 대한전기학회논문지:시스템및제어부문D
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• 제51권5호
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• pp.212-219
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• 2002

In this paper, the epipolar geometry, genera17y used as a pin-hole camera model, is newly adapted to our proposed method that enables the affine reconstruction of the 3D object from two projected views. The proposed method models the projective projection of inherent X-ray imaging system, obviates the need to attach artifirially constructed material on the body, and requires none of the prior-knowledge regarding to intrinsic and extrinsic parameters of two X-ray imaging systems. The optimum numerical solution is obtained by applying the least mean square estimator to corresponding points on two projected X-ray planes. The performance of this proposed method is Quantitatively analyzed using computer synthesized model of Cochlear implantation electrodes. In simulated experiments, the propnsed method is insensitive to the added random noise, the scaling factor change, the center point change, and rotational angular change between two projection planes, as well as enables the stable 3D reconstruction in least square sense even in worst testing cases.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2003년도 춘계학술대회 논문집
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• pp.1634-1637
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• 2003

Any given object on the motor-driven turntable is pictured from 8 to 72 different views with a digital camera. 3D shape reconstruction is performed with the integrated software called by Scanware from these multiple digital photographs. There are several steps such as configuration, calibration, capturing, segmentation, shape creation, texturing and merging process during the shape reconstruction process. 3D geometry data can be exported to cad data such as Autocad input file. Also 3D image model is generated from 3D geometry and texture data, and is used to advertise the model in the internet environment. Consumers can see the object realistically from wanted views by rotating or zooming in the internet browsers with Scanbull spx plug-in. The spx format allows a compact saving of 3D objects to handle or download. There are many types of scan equipments such as laser scanners and photogrammetric scanners. Line or point scan methods by laser can generate precise 3D geometry but cannot obtain color textures in general. Reversely, 3D image modeling with photogrammetry can generate not only geometries but also textures from associated polygons. We got various 3D image models and introduced the process of getting 3D image model of an internet-connected watchdog robot.

• 한국진공학회지
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• 제2권2호
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• pp.171-180
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• 1993

X-선 광전자 분광법(XPD)을 이용하여 GaAs(110) 절개면의 결정구조를 이해하였다. 각분해 X-선 분광법으로 GaAs(110) 면의 내각준위 Ga 및 As 3d의 스펙트럼을 얻어, 이 내각 준위의 세기 비율(intensity ratio)의 방위각과 편각에 따른 변화를 SSC(Single Scattering Cluster) 모델에서 얻은 회절패턴으로 곡선분석(fitting)하여 절개면의 재구성 구조(reconstruction geometry)를 얻었다. 이 절개면의 재구성된 값은 다른 실험의 결과와 비슷하였다.

• 한국광학회:학술대회논문집
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• 한국광학회 1991년도 제6회 파동 및 레이저 학술발표회 Prodeedings of 6th Conference on Waves and Lasers
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• pp.156-161
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• 1991

결상 홀로그램(image hologram)을 제작할 때 물체의 실상을 얻는 방법으로는 렌즈 등의 광학계를 이용하거나 다른 홀로그램에서 재생된 실상을 이용하는 방법 등이 있다. 본 연구에서는 결상 홀로그램을 제작하기 위하여 홀로그램에서 실상을 재생할 때, 재생빔으로 diverging spherical wave를 사용하는 geometry를 제안하고 문제점-재생된 실상의 상배를 변화와 홀로그램 수차들을 논의하였다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2005년도 추계종합학술대회
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• pp.391-394
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• 2005

In this paper, we present an approach that is able to reconstruct 3 dimensional metric models from un-calibrated images acquired by a freely moved camera system. If nothing is known of the calibration of either camera, nor the arrangement of one camera which respect to the other, then the projective reconstruction will have projective distortion which expressed by an arbitrary projective transformation. The distortion on the reconstruction is removed from projection to metric through self-calibration. The self-calibration requires no information about the camera matrices, or information about the scene geometry. Self-calibration is the process of determining internal camera parameters directly from multiply un-calibrated images. Self-calibration avoids the onerous task of calibrating cameras which needs to use special calibration objects. The root of the method is setting a uniquely fixed conic(absolute quadric) in 3D space. And it can make possible to figure out some way from the images. Once absolute quadric is identified, the metric geometry can be computed. We compared reconstruction image from calibrated images with the result by self-calibration method.

• Nuclear Engineering and Technology
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• 제45권4호
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• pp.529-538
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• 2013

Scattered photons cause blurring and distortions in flash radiography, reducing the accuracy of image reconstruction significantly. The effect of the scattered photons is taken into account and an iterative deduction of the scattered photons is proposed to amend the scattering effect for image restoration. In order to deduct the scattering contribution, the flux of scattered photons is estimated as the sum of two components. The single scattered component is calculated accurately together with the uncollided flux along the characteristic ray, while the multiple scattered component is evaluated using correction coefficients pre-obtained from Monte Carlo simulations.The arbitrary geometry pretreatment and ray tracing are carried out based on the customization of AutoCAD. With the above model, an Iterative Procedure for image restORation code, IPOR, is developed. Numerical results demonstrate that the IPOR code is much more accurate than the direct reconstruction solution without scattering correction and it has a very high computational efficiency.

• Journal of Mechanical Science and Technology
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• 제20권12호
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• pp.2034-2042
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• 2006

In this study, a complete 3D surface reconstruction method is proposed based on the concept that the vertices, of surface model can be completely matched to the unstructured point cloud. In order to generate the initial mesh model from the point cloud, the mesh subdivision of bounding box and shrink-wrapping algorithm are introduced. The control mesh model for well representing the topology of point cloud is derived from the initial mesh model by using the mesh simplification technique based on the original QEM algorithm, and the parametric surface model for approximately representing the geometry of point cloud is derived by applying the local subdivision surface fitting scheme on the control mesh model. And, to reconstruct the complete matching surface model, the insertion of isolated points on the parametric surface model and the mesh optimization are carried out. Especially, the fast 3D surface reconstruction is realized by introducing the voxel-based nearest-point search algorithm, and the simulation results reveal the availability of the proposed surface reconstruction method.

• 한국수학교육학회:학술대회논문집
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• 한국수학교육학회 2007년도 제38회 전국수학교육연구대회 프로시딩
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• pp.37-50
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• 2007

평면도형의 탐구에서 기본이 되는 것은 무엇이며, 그것으로부터 평면도형의 내용들을 일관성 있게 구성할 수는 없는가? 이 글에서는 평면도형 탐구의 기본 요소가 삼각형이라는 관점을 제시하고, 삼각형을 중심으로 한 평면도형 탐구 활동 설계 및 교과서 내용 재구성의 몇 가지 예를 제시한다. 그리고 이러한 관점 및 설계가 지니는 수학교육적 의의에 대하여 논의한다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.1885-1888
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• 2004

In order to render 3D model of the bone, the stack of cross-sectional images must be reconstructed from a series of X-ray radiographs, served as the projections. In the case where the distance between x-ray source and detector is not infinite, image reconstruction from projection based on parallel-beam geometry provides an error in the cross-sectional image. In such case, image reconstruction from projection based on conebeam geometry must be exercised instead. This paper is devoted to the determination of detector center for SART conebeam Technique which is critically effect the performance of the resulting 3D modeling.

• 한국진공학회지
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• 제10권1호
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• pp.93-97
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• 2001

본 논문에서는 방사광 X선을 이용하여 표면의 원자구조를 연구하기 위하여 국내 최초로 제작된 초고진공 X-선 산란 장치의 구조 및 성능을 소개한다. 초고진공 X-선 산란 장치는 초고진공에서의 표면처리를 위한 진공부분과 S2D2 geometry를 이용한 수평수직 X-선 회절기로 구성되어 있다. 본 장치의 성능은 Si(111) 표면의 7$\times$7 reconstruction 구조를 관찰함으로서 시연되었다. 본 장치를 이용하여 약 1600$\AA$ 이상의 7$\times$7 도메인으로부터 초당 216 counts의 $(1,{\frac{3}{7}})$ 피크가 관측되었고, 이것으로 본 장치의 진공도와 X-선 회절기의 기능이 표면원자구조를 연구하기에 적합함을 확인할 수 있었다