• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2003.05a
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• pp.808-812
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• 2003

The technology and concept of multimedia expands with the rapid growth of Digital technology. Digital broadcasting has already begun and movie industry is also switching the way of visualization from analog to digital. Image compositing is the core of the computer graphics related multimedia technology. Currently, various computer graphic technologies are being developed. Nevertheless, image compositing are being done manually because of not only the expensiveness image compositing equipments, but also the lack of experts in this area. This paper present a new image compositing technique for 3-Dimensional graphics and digital sources. A 2-Dimensional subject which will be used as a background was expanded into a 3-Dimensional by using the tracking technique. Thereafter, Effective image compositing has been obtained by precisely cooperating digital source images and 3-Dimensional model using 3-Dimensional graphics editing tool.

• Journal of the Korea Computer Graphics Society
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• v.14 no.1
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• pp.27-33
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• 2008

Mobile systems have relatively limited resources such as low memory, slow CPU, or low power comparing to desktop systems. In this paper, we present a new 3D mesh connectivity coding algorithm especially optimized for mobile systems(i.e., mobile phones). By using adaptive octree data structure for vertex positions, a new distance-based connectivity coding is proposed. Our algorithm uses fixed point arithmetic and minimizes dynamic memory allocation, appropriate for mobile systems. We also demonstrate test data to show the utility of our mobile 3D mesh codec.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.8
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• pp.1891-1898
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• 2013

To efficiently execute 3D graphic APIs, such as OpenGL and Direct3D, special purpose arithmetic unit(SFU) which supports floating-point sine, cosine, reciprocal, inverse square root, base-two exponential, and logarithmic operations is designed. The SFU uses second order minimax approximation method and lookup table method to satisfy both error less than 2 ulp(unit in the last place) and high speed operation. The designed circuit has about 2.3-ns delay time under 65nm CMOS standard cell library and consists of about 23,300 gates. Due to its maximum performance of 400 MFLOPS and high accuracy, it can be efficiently applicable to mobile 3D graphics application.

• Journal of the Korea Computer Graphics Society
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• v.3 no.2
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• pp.77-84
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• 1997

Solid modeling refers to techniques for unambiguous representations of three- dimensional objects. The most widely used techniques for solid modeling have been Constructive Solid Geometry (CSG) and Boundary Representation (BRep). Contemporary solid modeling systems typically support both representations, and bilateral conversions between CSG and BRep are essential. However, computing a CSG from a BRep is largely an open problem. This paper presents 3D geometric reasoning algorithms for converting a BRep into a special CSG, called Destructive Solid Geometry (DSG) whose Boolean operations are all subtractions. The major application area of BRep-to-DSG conversion is feature recognition, which is essential for integrating CAD and CAM.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.188-191
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• 2002

This paper concerns 3-D graphical modeling and simulation techniques for design and control of automated equipment for construction and facility maintenance. A case study on the use of 3-D graphics techniques for developing a power plant maintenance robot is presented. By simulating equipment operation within the 3-D geometry models of the work environment the environment design was improved. The 3-D graphical models of the equipment and the work environment were further utilized for the control of the robot from a remote distance. By presenting the real-time updated equipment configuration and the work environment to the operator, the graphical model-based equipment control system helped the operator overcome the problems associated with spatial perception. The collision between the robot and the plant structures was also avoided based the real-time analysis of the dynamically updated graphical models.

• Journal of the Korea Computer Graphics Society
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• v.11 no.1
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• pp.40-49
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• 2005

Several optimization techniques have been proposed for volume ray casting, but these cannot achieve real-time frame rates. In addition, it is difficult to apply them to some applications that require perspective projection. Recently, hardware-based methods using 3D texture mapping are being used for real-time volume rendering. Although rendering speed approaches real time, the larger volumes require more swapping of volume bricks for the limited texture memory. Also, image quality deteriorates compared with that of conventional volume ray casting. In this paper, we propose a data structure for real-time volume ray casting named PERM (Precomputed dEnsity and gRadient Map). The PERM stores interpolated density and gradient vector for quantized cells. Since the information requiring time-consuming computations is stored in the PERM, our method can ensure interactive frame rates on a consumer PC platform. Our method normally produces high-quality images because it is based on conventional volume ray casting.

• Journal of the Korea Computer Graphics Society
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• v.29 no.3
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• pp.93-103
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• 2023

The problem of reconstructing three-dimensional models of people and objects from color and depth images captured by low-cost RGB-D cameras has long been an active research area in computer graphics. Color and depth images captured by low-cost RGB-D cameras are represented as point clouds in three-dimensional space, which correspond to discrete values in a continuous three-dimensional space and require additional surface reconstruction compared to rendering using polygonal models. In this paper, we propose an effective ray-tracing based technique for visualizing point clouds rather than polygonal models. In particular, our method shows the possibility of an effective rendering method even in mobile environment which has limited performance due to processor heat and lack of battery.

• Journal of the Korea Computer Graphics Society
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• v.2 no.2
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• pp.69-74
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• 1996

With the emergence of integrated global market and increased competition, many companies are interested in sharing the product model data. One of the solutions is to share the product model data over the computer network or the internet using a standard format. CAD/CAM, STEP, and internet technologies make it possible to share the product model data. This paper presents methods to visualize 3D STEP geometry data on the internet. To create an internet-based STEP model visualizer, the programming language Java and 3D scene description language VRML have been experimented. The STEP geometry data can be displayed either by Java applets of by a VRML browser. These visualization technologies are applied to a PDM development. Engineers who have a low cost web browser can share the expensive design information even at a remote site.

• Journal of the Korea Computer Graphics Society
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• v.2 no.2
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• pp.37-44
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• 1996

Networked virtual reality systems provide a consistent virtual world to the users, possibly distributed across long distances, and have been widely applied in the military, entertainment, and architectural areas. Large processing requirements, however, made these systems be mainly researched on the platforms of high-performance graphics workstations. This paper presents several problems when networked virtual reality systems are implemented on commodity PCs: two problems related with 3D graphical processing, and the other related with network bandwidth and transmission delay. We also suggest solutions to these problems and analyze their performance effect based on an architectural simulation application.

• Journal of Korea Game Society
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• v.2 no.1
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• pp.49-54
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• 2002

In this paper we propose the methodology for 3D background image construction in computer games. This methodology was developed based on TIP (Tour Into the Picture) using a vanishing line Proposed by Kang et at. The methodology Proposed in this study can simply implement a 3D background for a computer game with a background model which is very complex or based on a real picture. Compared to the graphics technologies generally used, the proposed methodology does not need the process of modeling elaborate 3D information of a background, and hence can display the background even on a low grade personal computer using a small reference image. TIP technology was successfully applied to the implementation of a background model for a computer game and was found to be appropriate especially for real time games.