• Journal of the Korea Computer Graphics Society
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• v.23 no.1
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• pp.57-65
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• 2017

In this paper, we present a dictionary learning method for reducing errors in point cloud models and reconstructing their geometry. For this, 3D feature information is extracted from the models which have a similar shape characteristic as the target model. Then a dictionary is constructed and the geometry is reconstructed using the dictionary. The presented method in this paper consists of the following three steps. First, a geometric patch is constructed from a similar model. Second, a morphological 3D feature of the acquired patch is learned. Third, a geometry reconstruction is performed using the learned dictionary. Finally, the error between the original model and the reconstruction result is calculated, and the accuracy of the reconstruction result is checked.

• Proceedings of the IEEK Conference
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• 2005.11a
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• pp.715-718
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• 2005

Mobile devices is getting to include more functions according to the demand of digital convergence. Applications based on 3D graphic calculation such as 3D games and navigation are one of the functions. 3D graphic calculation requires heavy calculation. Therefore, we need dedicated 3D graphic hardware unit with high performance. 3D graphic calculation needs a lot of complicated floating-point arithmetic operation. However, most of current mobile 3D graphics processors do not have efficient architecture for mobile devices because they are based on those for conventional computer systems. In this paper, we propose arithmetic units for special functions of lighting operation of 3D graphics. Transcendental arithmetic units are designed using approximation of logarithm function. Special function units for lighting operation such as reciprocal, square root, reciprocal of square root, and power can be obtained. The proposed arithmetic unit has lower error rate and smaller silicon area than conventional arithmetic architecture.

• Journal of the Korea Society of Computer and Information
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• v.17 no.11
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• pp.39-46
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• 2012

The development of the computer widens the expressive ways for the nature objects and the scenes. The cutting edge computer graphics technologies effectively create any images we can imagine. Although the computer graphics plays an important role in filming and video production, the status of the domestic contents production industry is not favorable for producing and research all at the same time. In digital composition, the match moving stage, which composites the captured real sequence with computer graphics image, goes through many complicating processes. The camera tracking process is the most important issue in this stage. This comprises the estimation of the 3D trajectory and the optical parameter of the real camera. Because the estimating process is based only on the captured sequence, there are many errors which make the process more difficult. In this paper we propose the method for correcting the tracking data. The proposed method can alleviate the unwanted camera shaking and object bouncing effect in the composited scene.

• Journal of the Korea Computer Graphics Society
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• v.26 no.3
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• pp.21-29
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• 2020

This study defines the pipeline for digital fashion contents production using CLO 3D, a 3D fashion design software that supports virtual clothing visualization as a cutting-edge simulation technology for fashion, and vuforia, a mobile platform augmented reality (AR) development kit for creating AR applications. The proposed production pipeline is organized in a method to produce a virtual clothing model through CLO 3D software through works of patterns, sewing lines, textures, etc., and AR contents based on computer vision techniques using the functions and properties of vuforia development kits in the Unity engine development environment. In addition, we present application method that can be practically utilized from the perspective of practical users, such as fashion designers and directors, by creating a new type of AR digital fashion contents directly as a flow of the defined production pipeline.

• Journal of Korea Game Society
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• v.4 no.3
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• pp.65-70
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• 2004

The conventional 3D graphic accelerator is mainly focused on high performance in the application area of computer graphic and 3D video game How ever the existing 3D architecture is not suitable for portable devices because of its huge power. So, we analyze the embedded 3D graphics renderer. After the analyzing, to reduce the power, triangle set-up stage and edge walking stage are executed sequentially while scan-line processing stage and span processing stage which control performance of 3D graphic accelerator are executed parallel.

• Proceedings of the KIEE Conference
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• 2000.11a
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• pp.89-91
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• 2000

This paper presents a new method for representing SSR(Subsynchronous Resonanace) Phenomena using 3-D computer graphics animation. A virtual power system simulation environment was made for simulation and visualization of SSR phenomena. It is anticipated that the proposed method would be helpful for the operator training as well as power system education.

• 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.13 no.4
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• pp.21-27
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• 2007

The 3D Delaunay triangulation is the most widely used method for the mesh creation via the triangulation of a 3D point cloud. However, the method involves a heavy computational cost and, hence, in many interactive applications, it is not appropriate for surface triangulation. In this paper, we propose an efficient triangulation method to create a surface mesh from a 3D point cloud. We divide a set of object points into multiple subsets and apply the 2D Delaunay triangulation to each subset. A given 3D point cloud is cut into slices with respect to the OBB(Oriented Bounding Box) of the point set. The 2D Delaunay triangulation is applied to each subset producing a partial triangulation. The sum of the partial triangulations constitutes the global mesh. As a postprocessing process, we eliminate false edges introduced in the split steps of the triangulation and improve the results. The proposed method can be effectively applied to various image-based modeling applications.

• Journal of the Korea Computer Graphics Society
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• v.2 no.1
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• pp.68-76
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• 1996

One of the major problems in GIS(Geographical Information Systems) involves acquiring 3-D terrain data. Because conventional methods such as land surveying or analysis of aerial photographs are costly, the method of using existing paper maps has been gaining considerable attention. This method demands three processing steps: 1) extraction of contours, 2) assignment of height values to the extracted contours, 3) reconstruction of 3-D terrain data. In this paper we systematically develop a procedure for acquiring 3-D terrain data from contour solutions. For the first two steps, we describe the necessary operations and roughly sketch solutions. For the last step, we propose an efficient raster-based algorithm and present the results of experiments with existing paper map images.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.43 no.9 s.351
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• pp.53-58
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• 2006

A Vertex Shader is designed to show more 3D graphics expressions, and to increase flexibility of the fixed function T&L (Transform and Lighting) engine. Design of this Shader is based on Vertex Shader 1.1 of DirectX 8.1 and OpenGL ARB. The Vertex Shader consists of four floating point ALUs for vectors operation. The previous 32bits floating point data type is replaced to 24bits floating point data type in order to design the Vertex Shader that consume low-power and occupy small area. A Xilinx Virtex2 300M gate module is used to verify behaviour of the core. The result of Synopsys synthesis shows that the proposed Vertex Shader performs 115MHz speed at the TSMC 0.13um process and it can operate as the rate of 12.5M Polygons/sec. It shows the complexity of 110,000 gates in the same process.