• Journal of the Korea Computer Graphics Society
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• v.3 no.1
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• pp.57-67
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• 1997

The navigation of virtual space comes down to the manipulation of the virtual camera. The movement of the virtual cameras has 6 degrees of freedom. However, input devices such as mouses and joysticks are 2D. So, the movement of the camera that corresponds to the input device is 2D movement at the given moment. Therefore, the 3D movement of the camera can be implemented by means of the combination of 2D and 1D movements of the camera. Many of the virtual space navigation browser use several navigation modes to solve this problem. But, the criteria for distinguishing different modes are not clear, somed of the manipulations in each mode are repeated in other modes, and the kinesthetic correspondence of the input devices is often confusing. Hence the user has difficulty in making correct decisions when navigating the virtual space. To solve this problem, we use a single navigation metaphore in which different modes are organically integrated. In this paper we propose a helicopter pilot metaphor. Using the helicopter pilot metaphore means that the user navigates the virtual space like a pilot of a helicopter flying in space. In this paper, we distinguished six 2D movement spaces of the helicopter: (1) the movement on the horizontal plane, (2) the movement on the vertical plane,k (3) the pitch and yaw rotations about the current position, (4) the roll and pitch rotations about the current position, (5) the horizontal and vertical turning, and (6) the rotation about the target object. The six 3D movement spaces are visualized and displayed as a sequence of auxiliary windows. The user can select the desired movement space simply by jumping from one window to another. The user can select the desired movement by looking at the displaced 2D movement spaces. The movement of the camera in each movement space is controlled by the usual movements of the joystick.

• KIPS Transactions on Computer and Communication Systems
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• v.3 no.4
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• pp.125-128
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• 2014

OpenGL ES(OpenGL for Embedded System) 2.0 is one of the most widely used 3D graphics API(application progrma interface) standard for smart phones and tablet PCs at this time. During programming with this API, they prefer desktop environment rather than the target mobile environment, which has relatively low computing power. Thus, we need to emulate the OpenGL ES 2.0 API on the desktop PCs, where only OpenGL API libraries are available. In this paper, we present technical difficulties and their solutions to emulate OpenGL ES 2.0 on desktop PCs. Our final implementation of OpenGL ES 2.0 emulation library works on desktop PCs and passed over more than 96% of the official CTS(conformance test suites) to prove the correctness of our implementation. Additionally, for the commercially available benchmark programs, our implementation shows equivalent execution speeds to the previous commercial OpenGL ES 2.0 implementations.

• 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.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1998.06b
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• pp.147-153
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• 1998

This paper provides a method for video augmentation using image interpolation. In computer graphics or augmented reality, 3D information of a model object is necessary to generate 2D views of the model, which are then inserted into or overlayed on environmental views or real video frames. However, we do not require any three dimensional model but images of the model object at some locations to render views according to the motion of video camera which is calculated by an SFM algorithm using point matches under weak-perspective (scaled-orthographic) projection model. Thus, a linear view interpolation algorithm is applied rather than a 3D ray-tracing method to get a view of the model at different viewpoints from model views. In order to get novel views in a way that agrees with the camera motion the camera coordinate system is embedded into model coordinate system at initialization time on the basis of 3D information recovered from video images and model views, respectively. During the sequence, motion parameters from video frames are used to compute interpolation parameters, and rendered model views are overlayed on corresponding video frames. Experimental results for real video frames and model views are given. Finally, discussion on the limitations of the method and subjects for future research are provided.

• Current Optics and Photonics
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• v.8 no.3
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• pp.246-258
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• 2024

In aerospace and energy engineering, the reconstruction of three-dimensional (3D) temperature distributions is crucial. Traditional methods like algebraic iterative reconstruction and filtered back-projection depend on voxel division for resolution. Our algorithm, blending deep learning with computer graphics rendering, converts 2D projections into light rays for uniform sampling, using a fully connected neural network to depict the 3D temperature field. Although effective in capturing internal details, it demands multiple cameras for varied angle projections, increasing cost and computational needs. We assess the impact of camera number on reconstruction accuracy and efficiency, conducting butane-flame simulations with different camera setups (6 to 18 cameras). The results show improved accuracy with more cameras, with 12 cameras achieving optimal computational efficiency (1.263) and low error rates. Verification experiments with 9, 12, and 15 cameras, using thermocouples, confirm that the 12-camera setup as the best, balancing efficiency and accuracy. This offers a feasible, cost-effective solution for real-world applications like engine testing and environmental monitoring, improving accuracy and resource management in temperature measurement.

• Journal of the Korea Computer Graphics Society
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• v.7 no.2
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• pp.11-19
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• 2001

This paper proposes a colored paper mosaic rendering technique based on image segmentation that can automatically generate torn and tagged colored paper mosaic effect. and 3D effect that come about in human-made mosaic work can be represented by generating shadow using difference of paper thickness. Previous method did not produce satisfactory results due to the ineffectiveness of having to use pieces of the same size. The proposed two methods for determination of paper shape and location that are based on segmentation can subdivide image area by considering characteristics of image. The first method is to generate Voronoi polygon after subdividing the segmented image again using quad tree. And the second method is to apply the Voronoi diagram on each segmentation layer. Through these methods, the characteristic of the image is expressed in more detail than previous colored paper mosaic rendering method and these methods enable to produce image that is closer to human-made mosaic work.

• Journal of the Korea Computer Graphics Society
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• v.3 no.2
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• pp.27-34
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• 1997

3-D image modeling is in high demand for automated visual inspection and non-destructive testing. It also can be useful in biomedical research, medical therapy, surgery planning, and simulation of critical surgery (i.e. cranio-facial). Image processing and image analysis are used to enhance and classify medical volumetric data. Analyzing medical volumetric data is very difficult In this paper, we propose a new image modeling method based on tetrahedrization to improve the visualization of three-dimensional medical volumetric data. In this method, the trivariate piecewise linear interpolation is applied through the constructed tetrahedral domain. Also, visualization methods including iso-surface, color contouring, and slicing are discussed. This method can be useful to the correct and speedy analysis of medical volumetric data, because it doesn't have the ambiguity problem of Marching Cubes algorithm and achieves the data reduction. We expect to compensate the degradation of an accuracy by using an adaptive sub-division of tetrahedrization based on least squares fitting.

• Proceedings of the Korean Information Science Society Conference
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• 2005.07a
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• pp.682-684
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• 2005

본 논문은 인체 스캔 데이터를 예제 데이터베이스로 사용하여 2차원 사진으로부터 3차원 아바타 모델을 생성하는 기술을 제안한다. 직접 기하학적인 변형을 통해 3차원 아바타를 생성하는 기존의 방법들과는 달리, 미리 스캔한 다수의 3차원 인체 형상 모델 데이터베이스를 사용하여 사진에 나타난 실루엣과 가장 일치하도록 기본 모델을 변형 및 계산함으로써 모델을 획득한다. 본 연구는 예제 기반의 모델 변형 방법이 가지는 사실적인 인체 모델 생성의 장점, 2차원 사진을 이용한 방법이 가지는 텍스쳐 매핑 및 실루엣 정보 반영의 장정을 모두 가진다. 변형된 모델은 텍스쳐 매핑을 가한 후 애니메이션을 적용하여 가상환경에 활용할 수 있다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.10a
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• pp.181-184
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• 2009

Authoring AR(augmented-reality) contents not only takes too much time and cost, but also needs the help of professionals in the areas of computer science, VR(virtual reality), AR, 3D computer graphics, computer vision, etc. This paper proposes an authoring tool to allow non-programmers as content creators to author AR contents easily and quickly. An ideal AR authoring tool, which is the goal of our research, faces four major challenges from a technical point of view: (1) easy and quick authoring, (2) strong power of expression, (3) ease of verification and validation, (4) interactive authoring and debugging. To tackle with the challenges, we employ the interactive framework approach using formal and visual specification techniques.

• Journal of Fashion Business
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• v.19 no.5
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• pp.63-76
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• 2015

The purpose of this study was to design a training program for utilization of 3D special makeup mask program. This study was conducted with a 3D computer graphics software program, for special makeup mask using a variety of creative educational models and case study with comparative analysis. The makeup program applied to the majors and liberal arts classes for program design. Inthis study, the selected major courses included ' stage make up ', make up application', and illustrations and color '. Students were required to take a class targeted to questionnaire completion and analysis. The research method included literature search, and Internet navigation, of experimental research. The research targeted select college students attending a 4-year university located in Dae-jeon, Korea. ETRI's "3D mask special makeup simulation program" was used in support. A survey of the study conducted from September 1, 2013, to August 30, 2014, showed a total of 94 additional statistical analyses. First, grade 3 44.6% was attained by 91.7% of the first year student majoring in liberal arts classes, Second, students' in the 3D special dress up mask program Interestingly, attained high recognition in its mastering, usability, and creativity. Furthermore, the major student satisfaction was higher for the '3D special makeup mask program. Third, students '3D special dress up was one of the biggest advantages of the program', the mask ' that models 3D ' faces. In addition, the student's delicate dress called for critical technology skills. It is thought to be suitable for practical training and improving the efficiency and performance if applied to universities and beauty schools, such as the regular high school curriculum through research.