• Journal of the Korea Computer Graphics Society
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• v.1 no.2
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• pp.234-240
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• 1995

광선추적법에서 계산시간의 대부분은 광선과 물체와의 교차 검사에 사용된다. 그러므로 빠른 교차검사는 광선추적 알고리즘의 속도 증가를 가져올 수 있다. 따라서 본 논문에서는 광선 추적 알고리즘을 이용하여 삼각형이나 사각형등의 물체로 구성된 이미지를 생성할 때 전처리과정(preprocessing)에서 미리 계산된 두 상수 vector $\hat{u}$과 $\hat{v}$을 이용하여 지금까지 알려진 방법보다 빠른 교차 검사를 수행함으로써 속도를 향상 시키는 방법을 제안한다. 또한 이 결과를 삼각형의 보간(interpolation)에서 뿐만 아니라, 적응분할(adaptive subdivision) 방법을 사용하는 래디오시티 모델(radiosity model)에서 자주 사용되는 일반 사각형에서의 효율적인 bilinear interpolation 기법을 제시한다.

• Journal of Plant Biotechnology
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• v.5 no.4
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• pp.197-200
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• 2003

Scalable Vector Graphics (SVG) has enabled a visually appealing, browser-based application for the display of Brassica sequences relative to Arabidopsis thaliana, and there are currently more than 70,000 B. napus Expressed Sequence Tags (ESTs) displayed. The client side of this browser is based on a Custom Graphical User Interface (CGUI) library which uses SVG, a new web graphics standard, to provide windowing functionality inside the web browser. This windowing functionality, combined with asynchronous data retrieval and client side rendering overcomes two of the key technology imposed drawbacks of current web based browsers: Fixed displays and frequent page reloads. The end result is an intuitive and enjoyable browsing experience. The browser is accessible online from the Brassica / Arabidopsis Genomics Initiative (http://brassica.agr.gc.ca). Inquiries about the browser should be directed to LewisCT@agr.gc.ca.

• 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 Institute of Information and Communication Engineering
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• v.11 no.3
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• pp.563-569
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• 2007

As the mobile communication and the semiconductor technology is improved continuously, mobile contents such as the multimedia service and the 2D/3D graphics which require high level graphics are serviced recently. Mobile chips should consume small die area and low power. In this paper, we design a truncated floating-point multiplier that is useful for the 2D/3D vector graphics in mobile devices. The truncated multiplier is based on the radix-4 Booth's encoding algorithm and a truncation algorithm is used to achieve small area and low power. The average percent error of the multiplier is as small as 0.00003% and neglectable for mobile applications. The synthesis result using 0.35um CMOS cell library shows that the number of gates for the truncated multiplier is only 33.8 percent of the conventional radix-4 Booth's multiplier.

• The KIPS Transactions:PartB
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• v.13B no.3 s.106
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• pp.295-300
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• 2006

The integral imaging system is an auto-stereoscopic display that allows users to see 3D images without wearing special glasses. In the integral imaging system, the 3D object information is taken from several view points and stored as elemental images. Then, users can see a 3D reconstructed image by the elemental images displayed through a lens array. The elemental images can be created by computer graphics, which is referred to the computer-generated integral imaging. The process of creating the elemental images is called image mapping. There are some image mapping methods proposed in the past, such as PRR(Point Retracing Rendering), MVR(Multi-Viewpoint Rendering) and PGR(Parallel Group Rendering). However, they have problems with heavy rendering computations or performance barrier as the number of elemental lenses in the lens array increases. Thus, it is difficult to use them in real-time graphics applications, such as virtual reality or real-time, interactive games. In this paper, we propose a new image mapping method named VVR(Viewpoint Vector Rendering) that improves real-time rendering performance. This paper describes the concept of VVR first and the performance comparison of image mapping process with previous methods. Then, it discusses possible directions for the future improvements.

• Proceedings of the KIEE Conference
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• 1994.11a
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• pp.345-348
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• 1994

A real-time collision avoidance algorithm for an AMR (Autonomous Mobile Robot) using the Distance Transform and Vector Field Histogram is studied. This approach enables AMR to find a collision-free path with the unknown obstacles. All system parameters including positions of the obstacles can be accepted using a mouse icon and all the obtained trajectories can be displayed on a computer monitor in graphics.

• Proceedings of the Korea Contents Association Conference
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• 2007.11a
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• pp.543-546
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• 2007

Flow visualization is one of visualization techniques and it means a visual expression of vector data using 2D or 3D graphics. It aims for human to easily find and understand a special feature of the vector data. The Image Based Flow Visualization (IBFV) is one of the fastest technique in the dense integration based flow visualization techniques. In this paper, IBFV is accelerated and implemented using commodity GPU. Especially, mesh advection is accelerated at the vertex program.

• Journal of Korea Multimedia Society
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• v.11 no.6
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• pp.755-763
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• 2008

Silhouette is useful in computer graphics for a number of techniques such as non-photorealistic rendering, silhouette clipping, and blueprint generating. Methods for generating silhouette are classified into three categories: image-based, object-based, and hybrid-based. Hybrid-based method is effective in terms of time complexity but spatial coherence problem still remains. In this paper, we proposed a new hybrid-based method which produces 3D data for silhouette and also guarantees no spatial coherence problem. To verify the efficiency of the proposed algorithm, several experiments are conducted for various 3D models from simple to quite complex. Results show that our algorithm generates no gap between any two consecutive silhouette lines when the silhouette model is magnified significantly.

• Journal of Korea Multimedia Society
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• v.24 no.4
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• pp.528-537
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• 2021

Face recognition has gained significant notice because of its application in many businesses: security, healthcare, and marketing. In this paper, we will present the recognition method using the combination of correlation filters (CF) and Support Vector Machine (SVM). Firstly, we evaluate the performance and compared four different correlation filters: minimum average correlation energy (MACE), maximum average correlation height (MACH), unconstrained minimum average correlation energy (UMACE), and optimal-tradeoff (OT). Secondly, we propose the machine learning approach by using the OT correlation filter for features extraction and SVM for classification. The numerical results on National Cheng Kung University (NCKU) and Pointing'04 face database show that the proposed method OT-SVM gets higher accuracy in face recognition compared to other machine learning methods. Our approach doesn't require graphics card to train the image. As a result, it could run well on a low hardware system like an embedded system.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.3
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• pp.451-457
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• 2009

Most of objects in computer graphics may be represented by a form of mesh. The exact computation of vertex normal vectors is essential for user to apply a variety of geometric operations to the mesh and get more realistic rendering results. Most of the previous algorithms used a weight which resembles a local geometric property of a vertex of a mesh such as the interior angle, the area, and so on. In this paper, we propose an efficient algorithm for computing the normal vector of a vertex in meshes. Our method uses the conformal mapping which resembles synthetically the local geometric properties, and the mean value coordinates which may smoothly represent a relationship with the adjacent vertices. It may be confirmed by experiment that the normal vector of our algorithm is more exact than that of the previous methods.