• Journal of the Korea Computer Graphics Society
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• v.7 no.1
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• pp.27-35
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• 2001

Shadows are important elements in producing a realistic image. In rendering. generation of the exact shape and position of shadow is crucial in providing the user with visual cues on the scene. While the shadow map technique quickly generates a shadow for the scene wherein objects and light sources are fixed. it gets slow down as they start to move. In this paper. we apply an image-based rendering technique to generate shadows in real-time using graphics hardware. Due to the heavy requirement of storage for a shadow map repository. we use a wavelet-based compression scheme for effective compression. Our method will be efficiently used in generating realistic scenes in many real-time applications such as 3D games and virtual reality systems.

• Journal of the Korea Fashion and Costume Design Association
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• v.7 no.2
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• pp.1-10
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• 2005

This study intends to examine extensively on the current situation where the full capacity of 3D CG is not being highlighted because of the lack of the information and the awareness and to look at how the virtual reality technology is being applied ranging from the design of the clothes to the marketing. A set of processes ranging from the development of the clothing design to the marketing will be performed on the web. Designers will design with 3D CG and make the patterns and will hand this over to the producer together with the virtual swatch. But there are important problems to work out. First, it is the problem of the virtual fitting room. Second, it is the absence of the 3D CG, which is easy and convenient for the clothing design. Third, it is to perfect the visual reconstruction. Fourth, it is the security of the distribution system. Fifth, it also calls for the strengthened internet network that can smooth the flow of the tremendous data. Consumer will be able to produce according to their needs and will become designer and producer at the same time, resulting in the achievement of the consumer-oriented marketing in real sense.

• Journal of the Korea Computer Graphics Society
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• v.15 no.2
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• pp.1-8
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• 2009

This paper introduces a virtual dress up system, according to user's input model and garment image. At first step, we deform the garment image by using skeleton structures and ARAP method. Next step, sampling the boundary points and find their matching vertices which are used for optimizing the boundary fitting. In 2D rendering of the dress up, they have some unrealistic results, so we reconstruct the garment mesh to the 3D mesh. Rendering from the reconstructed 3D mesh, we can get the final dress up result. We present that our system produce a visually plausible and well-fitted virtual dress up results.

• Proceedings of the Korea Information Processing Society Conference
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• 2006.11a
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• pp.93-96
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• 2006

2D 및 입체 영상 콘텐츠의 공급이 많아지면서 실감 콘텐츠에 대한 관심이 더욱 높아지고 있다. 실감 콘텐츠는 다시점 카메라로부터 획득한 다시점 비디오, 깊이 카메라에서 얻은 RGB 영상과 컴퓨터 그래픽스와 같은 synthetic data를 합성하여 보다 실감나게 제작된다. 다시점 카메라를 이용하면 다시점 비디오를 쉽게 획득할 수 있으나 제작비용이 많이 들고, 깊이 카메라를 사용하면 시스템 구성은 상대적으로 용이하나 시점 영상이 하나라는 단점이 있다. 본 논문에서는 깊이 카메라에서 얻은 RGB 텍스쳐 데이터와 깊이 데이터로부터 가상 다시점 영상을 생성하고, 생성된 영상에 컴퓨터 그래픽스를 합성하는 방법을 제안한다. 제안한 방법은 다시점 카메라 시스템을 사용하지 않고도 시점에 따른 가상 시점 화상을 용이하게 제작하여 그래픽 객체를 합성한다. 합성된 다시점 3D 모니터나 입체 모니터를 이용하여 3차원으로 실감나게 시청할 수 있다.

• Journal of KIISE:Computing Practices and Letters
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• v.15 no.6
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• pp.454-458
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• 2009

The technology of virtual environments has been developed with better-quality appearance on a computer display in mind, but without consideration for objects' precise measurements in physical units. With the increased application of computer graphics in a variety of areas, there is a need for precise measurement functionality in addition to visualization. This paper describes the definition of physical properties using measurement units for X3D based virtual objects, to provide their precise physical information in virtual environments. To this end, we have included the physical property node in the X3D specification. The physical measurement units, such as length, mass, time, temperature, etc., are based on SI units (International System of Units).

• Journal of the Korea Computer Graphics Society
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• v.21 no.3
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• pp.11-16
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• 2015

We present a system for generating 3D personalized figures. This system provides 3D figures model modification and combination functions based on the content-awareness. The integrity of the 3D model must be guaranteed at the time of slicing of the 3D model for 3D printing. In addition to this, with 3D printing, we generally have to print a hollow model in order to save money, time, and the integrity of the print. This paper proposes the automatic algorithm that creates the 3D individual figures with depth sensor and the easy UI functions for deformation, thickness adjustment, and combination of the generated 3D figures model based on the content-awareness. Our proposed method maintains the unique features of the generated 3D figures and ensures the successful 3D printing.

• Proceedings of the Korea Information Processing Society Conference
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• 2006.05a
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• pp.1311-1314
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• 2006

원자력 시설 및 연구용 원자로 해체 시 해체 공정의 효율성을 증진시키기 위해 컴퓨터 그래픽스를 이용한 해체 공정의 최적화 연구가 수행되었다. 애니메이션 설계를 위해 해체 시설 및 구조물과 해체 장비의 모델링이 완료되었으며, 방사능에 오염된 대상물의 방사능 분포도를 위치별, 준위별로 확인할 수 있도록 3 차원으로 나타내었다. 해체 일정과 해체 폐기물량 그리고 해체 비용을 모사하기 위해 각 정보들에 대한 평가식과 가중치 값을 도출하였다. 연구로 1 호기 Thermal column 을 대상으로 애니메이션을 통한 해체 공정절차 시각화와 단위 해체 공정 시나리오를 수행한 결과 애니메이션의 경우 해체 현장과 동일하게 모델링 되어 현장 작업자들이 해체 공정 절차를 쉽게 이해할 수 있다는 것을 확인하였으며, 시나리오 별 해체 소요시간과 폐기물량 그리고 해체 비용의 경우 정상적으로 모사가 수행됨으로써 단위 해체 공정에 대한 최적의 시나리오를 평가 할 수 있는 기초 연구의 틀을 마련하였다. 본 시스템은 해체 관리자, 해체 시스템 분석가, 해체 현장 감독과 해체 작업자들의 중요한 협업도구로 활용될 것으로 사료된다.

• Journal of the Korea Computer Graphics Society
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• v.18 no.1
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• pp.1-9
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• 2012

Video-based modeling / rendering developed to produce photo-realistic video contents have been one of the important research topics in computer graphics and computer visions. To smoothly combine original input video clips and 3D graphic models, geometrical information of light sources and cameras used to capture a scene in the real world is essentially required. In this paper, we present a simple technique to estimate the position and orientation of an optimal light source from the topology of objects and the silhouettes of shadows appeared in the original video clips. The technique supports functions to generate well matched shadows as well as to render the inserted models by applying the estimated light sources. Shadows are known as an important visual cue that empirically indicates the relative location of objects in the 3D space. Thus our method can enhance realism in the final composed videos through the proposed shadow generation and rendering algorithms in real-time.

• Journal of the Korea Computer Graphics Society
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• v.9 no.2
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• pp.11-18
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• 2003

For extracting geometric features in 3D meshes according to user-steering with effective interactions. this paper generalizes the 2D algorithms of snapping and wrapping that. respectively. moves a cursor to a nearby feature and constructs feature boundaries. First. we define approximate curvatures and move cost functions that are the numerical values measuring the geometric characteristics of the meshes, By exploiting the measuring values. the algorithms of geometric snapping and geometric wrapping are developed and implemented. We also visualize the results from applying the algorithms to extracting geometric features of general 3D mesh models such as a face model and a tooth model.

• Journal of the Korea Computer Graphics Society
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• v.16 no.3
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• pp.11-19
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• 2010

This paper describes how to define and implement the schema for 3D virtual objects with physical units so that the objects can be compared in virtual environments based on physical properties, such as length, according to the specified units. We define physical units for virtual objects using the International System of Units and based on the X3D (Extensible 3D) specification. The schema must be defined with validation so that it does not violate the original X3D data structure. In this paper, we have extended the original X3D schema with a physical unit specification, and demonstrate the difference between units-specified and non-units-specified 3D scenes using an X3D browser that we developed.