• 한국HCI학회:학술대회논문집
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• 2007.02a
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• pp.915-919
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• 2007

가상현실은 컴퓨터를 이용하여 만들어진 가상의 환경에서 사용자가 오감을 통해 현실과 유사한 느낌을 경험할 수 있도록 해주는 기술이다. 햅틱 인터페이스는 사용자가 촉각으로 가상 환경과 상호 작용을 할 수 있도록 해주는 기술로서 사용자가 가상 물체를 실제로 만지는 듯한 착각을 불러 일으켜 보다 현실에 가까운 가상 경험을 할 수 있도록 도와준다. 본 논문에서는 다양한 용도로 사용할 수 있는 3차원 햅틱 인터페이스 장치를 설계 및 제작하고, 순발력 재활훈련의 목적으로 가상공간을 시각적으로 보여주는 입체영상 시스템과 연동하여 일부 제한적인 기능을 갖는 가상 테니스 연습 시스템을 구현하였다. 이때 가상 공과 가상 라켓의 간단한 충돌 모델과 햅틱 렌더링을 통하여 가상 공을 칠 때 사용자가 라켓으로 느끼는 충격과 반력을 제작한 3차원 햅틱 인터페이스 장치를 통하여 느낄 수 있도록 하였다. 구현된 시스템의 실험을 통하여 공과 라켓에서 충돌이 일어났을 때의 느낌을 사용자에게 전달할 수 있었으며, 완벽하지는 않지만 공과 라켓의 충돌 후 공의 나가는 방향과 속도가 실제와 유사함을 확인하였다.

• Smart Media Journal
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• v.2 no.4
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• pp.60-65
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• 2013

In this paper, we propose a high-resolution disparity map generation method using a low-resolution time-of-flight (TOF) depth camera and color camera. The TOF depth camera is efficient since it measures the range information of objects using the infra-red (IR) signal in real-time. It also quantizes the range information and provides the depth image. However, there are some problems of the TOF depth camera, such as noise and lens distortion. Moreover, the output resolution of the TOF depth camera is too small for 3D applications. Therefore, it is essential to not only reduce the noise and distortion but also enlarge the output resolution of the TOF depth image. Our proposed method generates a depth map for a color image using the TOF camera and the color camera simultaneously. We warp the depth value at each pixel to the color image position. The color image is segmented using the mean-shift segmentation method. We define a cost function that consists of color values and segmented color values. We apply a weighted average filter whose weighting factor is defined by the random walk probability using the defined cost function of the block. Experimental results show that the proposed method generates the depth map efficiently and we can reconstruct good virtual view images.

• Journal of Broadcast Engineering
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• v.24 no.5
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• pp.755-764
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• 2019

Currently commercially available light field cameras are difficult to acquire 5D light field video since it can only acquire the still images or high price of the device. In order to solve these problems, we propose a deep learning based method for synthesizing the light field video from monocular video. To solve the problem of obtaining the light field video training data, we use UnrealCV to acquire synthetic light field data by realistic rendering of 3D graphic scene and use it for training. The proposed deep running framework synthesizes the light field video with each sub-aperture image (SAI) of $9{\times}9$ from the input monocular video. The proposed network consists of a network for predicting the appearance flow from the input image converted to the luminance image, and a network for predicting the optical flow between the adjacent light field video frames obtained from the appearance flow.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38C no.10
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• pp.911-919
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• 2013

Evaluation of the effect of radial distortion for a holographic stereogram demands conducting an experiment which comprises rendering of a 3D obejc, acquisition of perspective images, rearrangement of the acquired images for hogel images and quality assessment of the observing image reconstructed from the holographic stereogram. We propose numerical implementation of this evaluation by a specially developed algorithm for modeling of all required steps. The modeling is done by using a numerical model of an optical engine for generation of radially distorted hogel images at various degrees of distortion. The distorted images are used to form the holographic stereogram and to make the numerically reconstructed images from the holographic stereogram which are observed by an observer at desired location. The reconstructed images are compared by using PSNR.

• 한국HCI학회:학술대회논문집
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• 2006.02a
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• pp.1069-1074
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• 2006

자동차/선박/정보통신기기 등의 각종 제조 산업 분야에서 신제품 개발기간과 비용단축을 위해 제품의 설계/스타일링 단계에서 디자인 및 사용자 사용성/편이성 등에 대해 가상으로 품평하는 기술에 대한 관심이 날로 증가하고 있다. 이상적인 가상 품평 기술은 사용자가 실물에 대한 품평 상황과 동일한 체험을 얻을 수 있도록 해야 한다. 이를 위해서 품평 대상물을 사실적으로 표현할 수 있도록 하는 실사 수준의 고품질 가시화 기술과 사용자가 품평 대상물을 자연스럽게 조작할 수 있는 상호작용 기술이 필요하다. 본 연구는 자동차의 내 외관 디자인 품평을 위한 가상 디자인 품평 시스템의 개발에 관한 것으로, 사실적인 자동차 가시화를 위한 환경 반사, 빛 산란, 범프 매핑등의 고품질 쉐이더 구현 및 저작 기술, 몰입환경에서 품평 작업을 위한 3D GUI 지원, 자동차 각 부품의 사용성/편이성 평가를 위한 운동성 조작 기능, 멀티프로젝션 디스플레이 시스템 및 3 차원 인간 모델, 장갑형 입력장치 지원을 통한 몰입형 가상 품평 환경 구축에 관한 기술 및 구현 방법을 제시하고자 한다.

• Journal of the Korea Computer Graphics Society
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• v.8 no.2
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• pp.9-14
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• 2002

In cases of densely occluded urban scenes, it is effective to determine the visibility of scenes, since only small parts of the scene are visible from a given cell. In this paper, we introduce a new visibility preprocessing method that efficiently computes potentially visible objects for volumetric cells. The proposed method deals with general 3D polygonal models and invisible objects jointly blocked by multiple occluders. The proposed approach decomposes volume visibility into a set of point visibilities, and then computes point visibility using hardware visibility queries, in particular HP_occlusion_test and NV_occlusion_query. We carry out experiments on various large-scale scenes, and show the performance of our algorithm.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.13 no.4
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• pp.171-177
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• 2013

Due to the demand for high speed 3D graphic rendering, video file format conversion, compression, encryption and decryption technologies, the importance of digital signal processor system is growing rapidly. In order to satisfy the real-time constraints, high performance digital signal processor is required. Therefore, as in general purpose computer systems, digital signal processor should be designed as multicore architecture as well. Using UTDSP benchmarks as input, the trace-driven simulation has been performed and analyzed for the 2 to 16-core digital signal processor architectures with the cores from simple RISC to in-order and out-of-order superscalar processors for the various window sizes, extensively.

• Journal of Korea Game Society
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• v.14 no.2
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• pp.77-84
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• 2014

Presence of soft shadow effects from an area light makes virtual scenes look more realistic. However, since computation of soft shadow effects takes a long time, acceleration methods are required to apply it to real-time 3D applications. Many researches assumed that area lights are white rectangles. We suggest a new method which renders soft shadows under the area light source having arbitrary shape and color. In order to approximate visibility test, we use a shadow mapping result near a pixel. Complexity of shadow near a pixel is used to determine degree of precision of our visibility estimation. Finally, our method can present more realistic soft shadows for the area light that have more general shape and color in real-time.

• Journal of Internet Computing and Services
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• v.18 no.3
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• pp.29-36
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• 2017

In these days, 3D dynamic simulation is closely related to many industries. In the past, physically-based 3D simulation was used mainly in the car crash or construction related fields, but it also plays an important role in movies or games today. Many mathematical computations are needed to represent the 3D object realistically, but it is difficult to process a large amount of calculations for simulation of application based on CPU in real-time. Recently, with the advanced graphic hardware and improved architecture, GPU can be utilized for the general purposes of computation function as well as graphic computation. Many approaches using GPU have been applied for various research fields. In this paper, we analyze the performance variation of two cloth simulation algorithms based on GPU according to the change of execution properties of GPU shaders in oder to optimize the performance of GPU-based cloth simulation. Cloth simulation is implemented by the spring centric algorithm and node centric algorithm with GPU parallel computing using compute shader of GLSL 4.3. We compare the performance of between these algorithms according to the change of the size and dimension of work group. The experiment is repeated to 10 times during 5,000 frames for each test and experimental results are provided by averaging of FPS. The experimental result shows that the node centric algorithm is executed in higher speed than the spring centric algorithm.

• Journal of the Korea Computer Graphics Society
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• v.24 no.3
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• pp.21-31
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• 2018

We introduces a system that enables fast and effective visualization of natural disaster data such as typhoons, tsunamis, floods, and flooding to help make informed decisions in disaster situations. Data containing disaster information consists of a few hundred megabytes to many tens and hundreds of gigabytes, which can not be handled by a PC. This system was implemented in the form of a client-server based service to generate and output results from high-performance servers. The server in a built-in, high-performance cluster handles client requests and sends the result of visualization to the client. Clients can receive the results in any form of images, videos, or 3D graphic model by specifying a desired time frame, effectively viewing the results with a user-friendly GUI.