• Journal of the Korea Computer Graphics Society
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• v.26 no.1
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• pp.7-15
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• 2020

In the process of visualizing a point set representing a smooth manifold surface, global illumination techniques can be used to render a realistic scene with various effects of lighting. Thanks to the continuous demand for ray tracing and the development of graphics hardware, dedicated GPUs and programmable pipeline for ray tracing have been introduced in recent years. In this paper, real-time global illumination rendering is studied for a point-set model using ray-tracing GPUs. We apply the moving least-squares (MLS) method to approximate the point set to a smooth implicit surface and render it using global illumination by performing massive ray-intersection tests with the surface and generating shading effects at the intersection point. As a result, a complicated point-set scene consisting of more than 0.5M points can be generated in real-time.

• Korea Multimedia Society
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• v.4 no.4
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• pp.31-42
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• 2000

• Proceedings of the KOSOMBE Conference
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• v.1991 no.05
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• pp.13-17
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• 1991

3차원 데이타로부터 물체 표면의 입체 도시를 위한 semi-transparent volume rendering 방법은 다른 입체 도시 방법들보다 화질면에서 뛰어나다고 알려져 있다. 본 논문에서는 이러한 semi-transparent volume rendering 방법의 장점을 가지면서 더욱 성능을 향상시킨 입체 데이타 표면의 3차원 도시를 실현시켜 보았다. Aniosotrophic resolution의 3차원 데이타는 directional interpolation을 사용하여 artifact의 발생을 줄였으며 전처리 과정에서 물체 표면까지의 깊이 정보를 구함으로써 계산시간을 줄일 수 있었고 또한 물체의 불투명도 값에 의해 결정되는 표본 간격을 사용함으로써 quantization error를 줄일 수 있었다.

• Archives of design research
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• v.13
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• pp.83-91
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• 1996

In this paper, proposed through the development process of a VCR the process of making exact three-dimensional modeling data using the Alias-one of the popular workstation in product design development process. At first, the features of the NURBS curve which is the basic curve in the modeling of Alias system and the methods of building surface are reviewed. The methods of rendering, lighting and textures are reviewed for application of realistic image presentation after building basic surfaces. The synthetic application methode of these factors necessary for the product design modeling is presented through the development process of a VCR.

• Proceedings of the Korea Contents Association Conference
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• 2005.11a
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• pp.13-18
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• 2005

Textures used in the game and VR environments with real-time rendering technology have different results according to used texture format supported video card. We propose some ideas for the texture using method by comparison with Frame Rate, Video Memory, and Quality.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2009.01a
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• pp.583-587
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• 2009

In this paper we propose a new method of Depth-Image-Based Rendering (DIBR) for Free-viewpoint TV (FTV). In the proposed method, virtual viewpoint images are rendered with 3D warping instead of estimating the view-dependent depth since depth estimation is usually costly and it is desirable to eliminate it from the rendering process. However, 3D warping causes some problems that do not occur in the method with view-dependent depth estimation; for example, the appearance of holes on the rendered image, and the occurrence of depth discontinuity on the surface of the object at virtual image plane. Depth discontinuity causes artifacts on the rendered image. In this paper, these problems are solved by reconstructing disparity information at virtual camera position from neighboring two real cameras. In the experiments, high quality arbitrary viewpoint images were obtained.

• 한국가시화정보학회:학술대회논문집
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• 2002.11a
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• pp.77-80
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• 2002

The recent 3D visualization such as volume rendering, iso-surface rendering or stream line visualization gives more understanding about structures or distribution of data in a space and, moreover, the real-time rendering of a scene enables the animation of time-series data. Because the meteorological data is frequently formed as multi-variables, 3-dimensional and time-series data, the spatial analysis, time-series analysis, vector display, and animation techniques can do important roles to get more understanding about data. In this research, our aim is to develop the 3-dimensional visualization techniques for meteorological data in the PC environment by using IDL. The visualization technology from :his research will be used as basic technology not only for the deeper understanding and the more exact prediction about meteorological environments but also for the scientific and spatial data visualization research in any field from which three-dimensional data comes out such as oceanography, earth science, or aeronautical engineering.

• Journal of KIISE:Computing Practices and Letters
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• v.8 no.6
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• pp.705-716
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• 2002

This paper proposes a method which visualizes MRI head data in 3 dimensions with direct volume rendering. Though surface rendering is usually used for MRI data visualization, it has some limits of displaying little speckles because it loses the information of the speckles in the surfaces while acquiring the information. Direct volume rendering has ability of displaying little speckles, but it doesn't treat MRI data because of the data features of MRI. In this paper, we try to visualize MRI head data in 3 dimensions as follows. First, we separate the brain region from the head region of MRI head data, next increase the pixel level of the brain region, then combine the brain region with the increased pixel level and the head region without brain region, last visualizes the combined MRI head data with direct volume rendering. We segment the brain region from head region based on histogram threshold, morphology operations and snakes algorithm. The proposed segmentation method shows 91~95% similarity with a hand segmentation. The method rather clearly visualizes the organs of the head in 3 dimensions.

• Journal of the HCI Society of Korea
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• v.1 no.1
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• pp.45-52
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• 2006

This paper presents an image-space algorithm to real-time collision detection, which is run completely by GPU. For a single object or for multiple objects with no collision, the front and back faces appear alternately along the view direction. However, such alternation is violated when objects collide. Based on these observations, the algorithm propose the depth peeling method which renders the minimal surface of objects, not whole surface, to find colliding. The Depth peeling method utilizes the state-of-the-art functionalities of GPU such as framebuffer object, vertexbuffer object, and occlusion query. Combining these functions, multi-pass rendering and context switch can be done with low overhead. Therefore proposed approach has less rendering times and rendering overhead than previous image-space collision detection. The algorithm can handle deformable objects and complex objects, and its precision is governed by the resolution of the render-target-texture. The experimental results show the feasibility of GPU-based collision detection and its performance gain in real-time applications such as 3D games.

• Journal of KIISE:Computing Practices and Letters
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• v.5 no.4
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• pp.385-394
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• 1999

제품을 설계하는 디자이너나 엔지니어는 많은 시간과 노력을 들이지 않고서 그들이 설계한 3차원 제품 모델에 대한 사실적인 이미지를 원한다. 디자인 프로세스의 초기인 개념 설계에서부터 설계검증, 그리고 가공 과정에서 사실적인 이미지가 매우 유용하므로, 대부분의 주요 CAD 제작사는 그들의 CAD 소프트웨어에 고급 렌더링 기능을 추가하고 있다. 상용의 CAD/CAM 모델러에서는 NURB 곡면을 기초로 모델링을 수행하므로, NURB 곡면을 렌더링할 수 있는 패키지가 필요하다. VIF(Visual InterFace) 렌더링 라이브러리는 A-buffer 방식과 Ray tracing 방식의 두 가지 고급 렌더링 모드를 제공한다. 다각형은 물론 NURB 곡면을 입력으로 받아 사용자가 설정한 표면의 각종 계수, 원하는 view와 설정된 광원에 따라 이미지를 만들고 다양한 형태로 출력시킬 수 있는 다양한 기능을 제공한다. 본 논문에서는 VIF 렌더링 라이브러리에 대한 구조와 기능별로 분류된 함수에 대하여 설명하며, 실제로 CAD/CAM 시스템과 통합되어 구상설계에서부터 3차원 설계 모델링에 이르기까지의 제조공정에서 설계검증 툴로써 어떻게 활용되고 있는가에 대하여 기술한다.Abstract Engineers and industrial designers want to produce a realistic-looking images of a 3D model without spending a lot of time and money. Photo-realistic images are so useful from the conceptual design, through its verification, to the machining, that most major CAD venders offer built-in as well as add-on photo-realistic rendering capability to their core CAD software. Since 3D model is consists of a set of NURB surfaces in commercial CAD packages, we need a renderer which handles NURB surface as well as other primitives.A new rendering library called VIF (Visual InterFace) provides two photo-realistic rendering modes: A-buffer and Ray tracing. As an input data it takes NURB surfaces as well as polygonal data and produces images in accordance with the surface parameters, view and lights set by user and outputs image with different formats. This paper describes the overall architecture of VIF and its library functions classified by their functionalities, and discusses how VIF is used as a graphical verification tool in manufacturing processes from the conceptual design to 3D modeling.