• 한국HCI학회:학술대회논문집
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• 한국HCI학회 2008년도 학술대회 1부
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• pp.461-468
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• 2008

가상현실 및 증강 현실 응용 특히 디지털 패션과 같은 응용분야에서 아바타에 여러 가지 형태의 의복을 입히고 장신구들을 장식하여 보다 현실감이 나는 3차원 애니메이션을 제작한 다음 인터넷을 통하여 개인용 컴퓨터는 물론 핸드폰 같은 휴대용 정보단말기에 표현하려는 요구가 증가하고 있다. 하지만 3차원 모델을 실감나게 표현하는데 필요한 데이터의 용량이 매우 크고 네트워크의 속도 문제와 단말기에 장착된 메모리 장치의 제한적인 성능 문제등으로 인하여, 3차원 영상의 효과적인 전송 및 실감나는 표현은 매우 어렵다. 본 논문에서는 3차원 애니메이션에서 사용되는 데이터를 압축하는데, 3차원 모델 데이터를 군집화하여 애니메이션에 필요한 저장 공간을 줄여서 휴대용 정보단말기에서도 3차원 모델을 자연스럽게 렌더링할 수 있게 하는 기법을 제안하고자 한다. 제안된 기법은 각종 디포머블 오브젝트에도 응용될 수 있으며, 기존의 정적인 형상 압축 기술과 연계하여 좀 더 높은 압축을 가능하게 할 것으로 기대된다.

• Fibers and Polymers
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• 제7권1호
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• pp.57-61
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• 2006

A study has been made on the quantification and evaluation of fabric pilling using two-dimensional and three-dimensional hybrid imaging methods. Two-dimensional imaging method was good for some samples while three-dimensional measurement method for others, according to the properties of their base fabric. Various image processing techniques as well as three-dimensional data processing algorithms were applied for the extraction of pills from measured data and a series of shape parameters have been defined for the objective evaluation of fabric pilling. An evaluation criterion that is compatible with the conventional evaluation method has been proposed by applying the new evaluation method to the current photographic standards.

• 한국정밀공학회지
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• 제20권12호
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• pp.205-212
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• 2003

Many people are exposed to accidents by vehicles or sports. The most frequent injuries by these accidents is concerned with a knee joint. The three-dimensional surface model of a knee is needed for dynamic analysis of knee motion and knee reconstruction. three-dimensional motion data of a knee joint were obtained using X-ray and precise magnetic sensors. The surface data of a femur and a tibia were obtained using cross-sectional pictures by CT. The three-dimensional surface models of a femur and a tibia were made by the method of optimal triangular patch. Using obtained motion data, we simulated the motion of three-dimensional knee joint model.

• 한국유체기계학회 논문집
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• 제6권1호
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• pp.30-36
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• 2003

This paper presents the analysis of flows through three different types of radial compressor impeller by using quasi-three-dimensional analysis method. The method obtains two-dimensional solution for velocity distribution on meridional plane, and then calculates approximately the static pressure distributions on blade surfaces. Finite difference method is used for the solutions of governing equations. The compressors have low level compression-ratio and 12 straight radial blades with no backsweep. The results are compared with experimental data and the results of three-dimensional inviscid analysis with those by finite element method. It is found that the agreements with experimental data are good for the cases where viscous effects are not dominant.

• Journal of Mechanical Science and Technology
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• 제17권11호
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• pp.1665-1673
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• 2003

We propose an image-based three-dimensional shape determination system. The shape, and thus the three-dimensional coordinate information of the 3-D object, is determined solely from captured images of the 3-D object from a prescribed set of viewpoints. The approach is based on the shape-from-silhouette (SFS) technique, and the efficacy of the SFS method is tested using a sample data set. The extracted three-dimensional shape is modeled with polygons generated by a new iterative triangulation algorithm, and the polygon model can be exported to commercial software. The proposed system may be used to visualize the 3-D object efficiently, or to quickly generate initial CAD data for reverse engineering purposes, including three dimensional design applications such as 3-D animation and 3-D games.

• International Journal of Air-Conditioning and Refrigeration
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• 제8권2호
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• pp.11-22
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• 2000

Holographic interferometric tomography can provide reconstruction of instantaneous three-dimensional gross flow fields. The technique however confronts ill-posed reconstruction problems in practical applications. Experimental data are usually limited in projection and angular scanning when a field is captured instantaneously or under the obstruction of test models and test section enclosures. An algorithm, based on a series expansion method, has been developed to improve the reconstruction under the ill-posed conditions. A three-dimensional natural convection flow around two interacting isothermal cubes is experimentally investigated. The flow can provide a challenging reconstruction problem and lend itself to accurate numerical solution for comparison. The refractive index fields at two horizontal sections of the thermal plume with and without an opaque object are reconstructed at a limited view angle of 80$\circ$. The experimental reconstructions are then compared with those from numerical calculation and thermocouple thermometry. It confirms that the technique is applicable to reconstruction of reasonably complex, three-dimensional flow fields.

• 한국가시화정보학회:학술대회논문집
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• 한국가시화정보학회 2005년도 추계학술대회 논문집
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• pp.58-63
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• 2005

Three-dimensional vortical structures in the wake behind a road vehicle has been visualized with the help of two-dimensional PIV measurement data. A three-dimensional velocity field has been reconstructed from several sectional measurement data in the x-y, y-z and z-x planes. Isovorticity surface observed by stacking only the sectional data in each plane, does not show the vortical structures within the recirculation region but represents only the strong shear flows. Thus, in the present study, the velocity component normal to the x-y plane is obtained by interpolating those velocities in the z-x plane. Then, a $\lambda_{2}$-definition which captures the local pressure minimum or vortex core, is applied to visualize the vortices in the recirculation region. The final results represent a successful configuration for the three-dimensional vortices.

• Journal of Advanced Marine Engineering and Technology
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• 제23권2호
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• pp.259-269
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• 1999

A new algorithm for measuring 3-D velocity components of high speed flows were developed using a digital image processing technique. The measuring system consists of three CCD cameras an optical instrument called AOM a digital image grabber and a host computer. The images of mov-ing particles arranged spatially on a rotation plate are taken by two or three CCD cameras and are recorderd onto the image grabber or a video tape recoder. The three-dimensionl velocity com-ponents of the particles are automatically obtained by the developed algorithm In order to verify the validity of this technique three-dimensional velocity data sets obtained from a computer simu-lation of a backward facing step flow were used as test data for the algorithm. an uncertainty analysis associated with the present algorithm is systematically evaluated, The present technique is proved to be used as a tookl for the measurement of unsteady three-dimensional fluid flows.

• 응용통계연구
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• 제30권3호
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• pp.345-362
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• 2017

자료 분석가가 대용량 데이터를 분석할 때 이해하기 쉽고 효과적으로 전달하기 위하여 다양한 데이터 시각화 방법들을 사용하고 있다. 그 중 3차원 그림은 2차원 화면상에서 입체로 표현하기 위하여 그림을 회전시켜야 한다. 이러한 단점을 보완하기 위하여 본 연구에서는 3차원 시각화 자료를 입체적으로 살펴보는 방법으로 가상현실을 이용한 두 가지 방식인 Batch method와 Real-time method를 제안하였다. 이 방법들을 통하여 3차원 시각화 자료를 입체적으로 살펴볼 때 3차원 구조를 좀 더 명확하게 확인할 수 있을 것이다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.94.5-94
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• 2001

Unrestricted measurement method of three-dimensional walking distance utilizing body acceleration and terrestrial magnetism is discussed. The three-dimensional walking distance is derived by the integration of the three dimensional acceleration of foot during swing phase. Since the sensor system attached on the foot rotates during swing phase, the acceleration data measured on the foot include acceleration of gravity which causes inaccurate calculation of the velocity and the distance. Three gyros are used to compensate the rotation of the sensor system. Moreover, one geomagnetic sensor is employed to derive the heading direction of the subject Healthy volunteers performed ...