• Economic and Environmental Geology
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• v.27 no.2
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• pp.191-199
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• 1994

We have developed an algorithm based on the method of integral equations to simulate the magnetotelluric (MT) responses of three-dimensional (3-D) bodies in a layered half-space. The inhomogeneities are divided into a number of cells and are replaced by an equivalent current distribution which is approximated by pulse basis functions. A matrix equation is constructed using the electric Green's tensor function appropriate to a layered earth, and is solved for the vector current in each cell. Subsequently, scattered fields are found by integrating electric and magnetic Green's tensor functions over the scattering current About a 3-D conductive body near the earth's surface, interpretation using 2-D transverse electric modeling schemes can imply highly erratic low resistivities at depth. This is why these routines do not account for the effect of boundary charges. However, centrally located profiles across elongate 3-D prisms may be modeled accurately with a 2-D transverse magnetic algorithm, which implicitly includes boundary charges in its formulation. Multifrequency calculations show that apparent resistivity and impedance phase are really two complementary parameters. Hence, they should be treated simultaneously in broadband MT interpretation.

• Journal of the Society of Naval Architects of Korea
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• v.29 no.2
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• pp.8-17
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• 1992

There has been considerable reseach on the representation of a hull form which is a 3-dimensional free surface. A form parameter method to describe the hull form by means of form parameters which represent the characteristics of the given hull form geometry has been recently paid special attention with the advent of powerful computer. However, there have been reported many problems to the conventional form parameter for the practical hull form generation. In the present paper, an attempt has been made to creak hull form by combining the form parameter method with the B-spline curve which can be best fitted to free surfaces. In an application, the present method is used to generates a Bulk carrier hull form and compared with the existing hull form to prove its applicability for the hull form generation.

• Journal of Korean Society for Geospatial Information Science
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• v.10 no.1 s.19
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• pp.19-26
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• 2002

To provide 3D GSIS data on the internet, 3D data structures need to be researched and applied for spatial analysis for subsurface modeling. As for GSIS software R&D trend the following things have pointed out : 3-dimensional geo-processing technologies, internet-based application system development, distributed processing technologies for large volume of spatial information, real-time geo-data processing methodologies, Among them research scope within Internet-based application system or Web-based GSIS generally contains core parts of software development such as Internet application, large volume of spatial database handling, real-time spatial data processing, spatial data transfer and transformation, and volumetric display of processing results. This study shows the method of providing 3D GSIS on the internet using VRML model, which are made of DEM data, draped aerial photo, and VRML script programming. And it is also studied that offering 3D GSIS engine on the internet and precise texture mapping using satellite image and aerial photos.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.42 no.3 s.303
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• pp.41-50
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• 2005

A novel image mosaicking technique suitable for 3D urban visualization is proposed. It is not effective to apply 2D image mosaicking techniques for urban visualization when, for example, one is filming a sequence of images from a side-looking video camera along a road in an urban area. The proposed method presents the roadside scene captured by a side-looking video camera as a continuous set of textured planar faces, which are termed 'multiple planes' in this paper. The exterior parameters of each frame are first calculated through automatically selected matching feature points. The matching feature points are also used to estimate a plane approximation of the scene geometry for each frame. These planes are concatenated to create an approximate model on which images are back-projected as textures. Here, we demonstrate algorithm that creates efficient image mosaics in 3D space from a sequence of real images.

• 한국HCI학회:학술대회논문집
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• 2007.02a
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• pp.1-7
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• 2007

본 논문은 3차원 스캐너로 획득된 실제 얼굴 데이터를 햅틱 상호작용을 통해 직접 변형하고 재질감을 모델링 하는 알고리즘을 제안한다. 제안된 알고리즘은 그래픽 하드웨어 기반의 햅틱 렌더링 알고리즘을 기반으로 획득된 2.5D 얼굴 데이터를 mass-spring 모델을 적용하여 변형하고 얼굴의 재질감(탄성, 마찰, 거칠기) 정보를 모델링 하는 것이다. 햅틱 장치를 이용한 변형알고리즘은 변형 시 효율적인 변형 영역 탐색을 위하여 공간 분할방법인 k-d 트리 구조를 이용하여 최근방 탐색 알고리즘을 구현하였으며, 사실적인 힘 계산을 위하여 각 포인트 마다 mass-spring 모델을 적용하여 반력 연산 및 물체의 변형을 수행하였다. 아울러 재질감을 모델링 하기 위해 깊이 이미지 기반 표현(Depth Image Based Representation, DIBR)을 이용하여 가상 물체의 거칠기, 탄성, 및 마찰을 편집할 수 있는 방법론을 제시하고, 편집된 재질감을 직접 물체의 표면에 적용하여 렌더링 하는 알고리즘을 제안한다.

• Korean Journal of Optics and Photonics
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• v.6 no.4
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• pp.274-281
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• 1995

The new method of recording and reconstructing a synthetic object, which was called as scannedobject holography (SOH), was proposed and its feasibility was demonstrated theoretically and experimentally. The hologram was recorded by interfering the fixed reference beam with spherical waves emitting from a moving point source, whose trajectory determined the shape of the synthetic object to be recorded. The end face of an optical fiber and the output from a pulsed laser were utilized in order to implement a moving point source experimentally. tally.

• Proceedings of the Korean Information Science Society Conference
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• 2005.11a
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• pp.715-717
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• 2005

3차원 스캔 데이터는 물체의 형상정보를 표현하는 Euclidian 공간상의 점데이터의 집합으로 정의될 수 있으며. 복잡한 3D 컨텐츠 및 모델을 사실적이고 효율적으로 생성하기 위한 기초 정보로 사용된다 최근 3차원 스캐닝기술의 발전으로 고정밀도의 형상정보뿐만 아니라 색상정보의 획득이 가능해 졌으며, 데이터의 용량이 비약적으로 증가하였다. 본 논문에서는 기존의 형상기반 점데이터 감소 방법의 한계를 극복하기 위해 색상이 동시에 고려되는 효율적인 점데이터 감소방법을 제안한다.

• Journal of KIISE:Software and Applications
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• v.32 no.1
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• pp.34-40
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• 2005

Despite the wide range of information and engineering visualization techniques available, studies in investigating the effectiveness of the techniques in visualization has been rare. The typical visualization techniques were CAD, 2D and 3D computer graphics, and virtual environment (VE) that use 3D displays of 3D. space. The objects of this study is to analyze the user preferences and workload changes according to the visualization methods of engineering drawings such as 2D CAD, 2D computer graphics, 3D computer graphics, and augmented reality which is a variation of VEs. The results showed that users preferred 3D visualization techniques to 2D visualization techniques, though there were no workloads differences. Furthermore, the 3D perspective of AR which analogies the real world could facilitate the interpretation of engineering drawings.

• Proceedings of the Korean Information Science Society Conference
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• 2003.04c
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• pp.217-219
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• 2003

본 논문에서는 실시간으로 상호작용이 가능한 광범위한 3차원의 넓은 외부영역을 렌더링하기 위해 공간문할 방법으로 제한적 옥트리를 이용하고, 충돌검출 방법으로 계층적 경계상자를 사용하여 효과적으로 충돌검출을 하는 방법을 소개한다. 넓은 외부 영역을 동적으로 빠르게 처리하기 위해 공간을 분할시켜 처리영역을 축소하고 3차원 공간을 고정볼륨 바운드를 구축한 후 이를 처리 값으로 이용한 계층적 경계상자를 이용하여 충돌처리를 한다. 옥트리는 정적인 물체에 대한 정확한 표현 시 주로 사용되나 본 논문에서는 이를 동적인 환경에 이용하기 위하여 제한적 OSF를 사용한다. 또한 폴리곤의 충돌검사를 모두 하지 않고 빠른 시간에 충돌검출을 판단할 수 있는 방법과 경계상자의 충돌검출에 대한 비용이 3차원 개체 개수에 대해 비례하여 증가하는 데에 대한 개선 방법을 제안한다.

• Journal of the Korea Computer Graphics Society
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• v.12 no.4
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• pp.1-5
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• 2006

This paper introduces the surface detailed painterly rendering using heightfield map. To do this, we implement painterly rendering using normal mapping and displacement mapping method by heightfield map. The suggested method can apply to the 3D visualization program and game engine for representing the surface detailed realtime rendering using GPU Programming.