• 대한전기학회논문지:전력기술부문A
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• 제48권5호
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• pp.636-642
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• 1999

The synthesis of the 3D images is the most important part of the virtual reality. The ray tracing is the best method for reality in the 3D graphics. But the ray tracing requires long computation time for the synthesis of the 3D images. So, we implement the ray tracing with software and hardware. Specially we design the hit-test unit with FPGA tool for the ray tracing. Hit-test unit is a very important part of ray tracing to improve the speed. In this paper, we proposed a new hit-test algorithm and apply the parallel architecture for hit-test unit to improve the speed. We optimized the arithmetic unit because the critical path of hit-test unit is in the multiplication part. We used the booth algorithm and the baugh-wooley algorithm to reduce the partial product and adapted the CSA and CLA to improve the efficiency of the partial product addition. Our new Ray tracing processor can produce the image about 512ms/F and can be adapted to real-time application with only 10 parallel processors.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1997년도 추계학술대회 논문집 학회본부
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• pp.402-404
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• 1997

The synthesis of the 3D images is the most important part of the virtual reality. The ray tracing is the best method for reality in the 3D graphics. But the ray tracing requires long computation time for the synthesis of the 3D images. So, we implements the ray tracing with software and hardware. Specially we designs the hit-test unit with FPGA tool for the ray-tracing.

• 한국태양에너지학회 논문집
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• 제31권3호
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• pp.36-41
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• 2011

Nowadays, the solar expose right is very important with people's life. Therefore, in calculating the sunshine hours, the point analysis and area analysis methods are used in previous studies. Previous two methods have merits and faults. Therefore, ray-tracing method is used as a alternative. Ray-tracing method is adopted by the software of Autodesk Ecotect which is a widely used program by the architectural company and academic university. In this study first, ray-tracing methodology is studied with how to calculate the overshadowing area and, secondly, the sensitivity of the two major factors, overshadowing accuracy and sky subdivision, is analyzed. With these results, appropriate application of the ray-tracing method is presented.

• 한국정보통신설비학회:학술대회논문집
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• 한국정보통신설비학회 2007년도 학술대회
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• pp.251-255
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• 2007

In this paper, propagation analysis method in using 3D Ray Tracing propagation model in wireless cell planning is proposed. Through 3D Ray Tracing model, we can predict the distribution of propagation loss of the received signal. For correct and a low complex analysis, Quad Tree and Pre-Ordering and Hash Function algorithms are included in 3D Ray Tracing algorithm. And 3D Ray Tracing model is embodied in CellTREK that is developed by KT and used to plan Wibro system analysis. In CellTREK, propagation analysis is performed and that result is represented in 3D viewer. In numerical results, it is showed that the proposed scheme outperforms Modified HATA model when comparing with measurement data.

• IEIE Transactions on Smart Processing and Computing
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• 제4권2호
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• pp.65-70
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• 2015

In this paper, we describe the world's first real-time ray-tracing chip architecture. Ray-tracing technology generates high-quality 3D graphics images better than current rasterization technology by providing four essential light effects: shadow, reflection, refraction and transmission. The real-time ray-tracing chip named RayChip includes a real-time ray-tracing graphics processing unit and an accelerating tree-building unit. An ARM Ltd. central processing unit (CPU) and other peripherals are also included to support all processes of 3D graphics applications. Using the accelerating tree-building unit named RayTree to minimize the CPU load, the chip uses a low-end CPU and decreases both silicon area and power consumption. The evaluation results with RayChip show appropriate performance to support real-time ray tracing in high-definition (HD) resolution, while the rendered images are scaled to full HD resolution. The chip also integrates the Linux operating system and the familiar OpenGL for Embedded Systems application programming interface for easy application development.

• 디지털콘텐츠학회 논문지
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• 제8권4호
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• pp.459-465
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• 2007

본 논문에서는 다중 벽면 구조의 실내 환경에서 전파의 전달특성을 모델링하기 위해 ray-launching 기반의 광선추적법을 이용한 2차원 ray-tracing 시뮬레이터를 구현하였고, 이를 통해 ray의 전파 경로를 분석하고 평가하였다. 실험 결과, 구현된 광선추적법의 경로 패턴 및 시간지연 분포는 동일한 무선 환경에서 수행된 이전의 실험 결과와 비슷한 결과가 나타남을 확인하였으며, 송수신 거리 및 방사각에 따른 수신반경의 조정이 타당함을 확인하였다. 특히 비가시거리 송수신 환경에서 다중 벽면을 투과한 ray가 반사와 투과를 형성하여 수신기에 도달할 때까지의 ray의 impulse response는 기존 연구의 실험 결과와 대부분 일치하였으며, 송신기에서 발사되는 ray의 방사각을 $1^{\circ}$에서 $7^{\circ}$까지 달리하여 실험한 경우 도출된 channel profile이 서로 유사함을 확인하였다.

• Journal of Communications and Networks
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• 제15권6호
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• pp.547-558
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• 2013

Ultra broadband communication systems operated at THz frequencies will require the thorough knowledge of the propagation channel. Therefore, an extensive measurement campaign of 50 GHz wide indoor radio channels is presented for the frequencies between 275 and 325 GHz. Individual ray paths are resolved spatially according to angle of arrival and departure. A MIMO channel is recorded in a $2{\times}2$ configuration. An advanced frequency domain ray tracing approach is used to deterministically simulate the THz indoor propagation channel. The ray tracing results are validated with the measurement data. Moreover, the measurements are utilized for the calibration of the ray tracing algorithm. Resulting ray tracing accuracies are discussed.

• 반도체디스플레이기술학회지
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• 제21권4호
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• pp.23-26
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• 2022

In this paper, our ray tracing hardware is implemented on the latest high-capacity FPGA board. The system included ray tracing hardware for rendering and tree building hardware for handling dynamic scenes. The FPGA board used in the implementation is a Xilinx Alveo U250 accelerator card for data centers. This included 12 ray tracing hardware cores and 1 tree-building hardware core. As a result of testing in various scenes in Full HD resolution, the FPS performance of the proposed ray tracing system was measured from 8 to 28. The overall average is about 17.7 FPS.

• 한국항행학회논문지
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• 제11권4호
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• pp.454-460
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• 2007

본 논문에서는 실내 환경에서 전파의 전달특성을 모델링하기 위해 광선추적법을 이용한 2차원 ray-tracing 시뮬레이터를 구현하였고, 이를 통해 다중 벽면으로 구성된 환경에서 ray의 전파 경로를 분석하고 평가하였다. 실험 결과, 구현된 광선추적법의 경로 패턴 및 시간지연 분포는 동일한 무선 환경에서 수행된 이전의 실험 결과와 비슷한 결과가 나타남을 확인하였으며, 송수신 거리 및 방사각에 따른 수신반경의 조절이 타당함을 확인하였다. 특히 비가시거리 송수신 환경에서 다중 벽면을 투과한 ray가 반사와 투과를 형성하여 수신기에 도달할 때까지의 channel profile은 기존 연구의 실험 결과와 유사함을 확인하였다.

• 한국정밀공학회지
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• 제22권12호
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• pp.100-107
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• 2005

The present work covers a new ray tracing scheme of an injection-molded plastic lens linked with finite element analysis fur injection molding processes. The traditional ray tracing schemes have been based on the assumption that optical property of the lens is homogeneous throughout the entire volume. However, this assumption is quite unrealistic for injection-molded plastic lenses since material properties vary at every point due to injection molding effects. In order to consider non-homogeneous property of a lens, a modified ray tracing method is proposed in connection with finite element analysis of injection molding. Through the analysis of the injection molding process, the distribution of refractive indices can be obtained. This information is then utilized in the proposed ray tracing scheme based on finite element meshes so as to take into account variation of the refractive indices. The effect of mold temperature is also investigated through finite element analysis, and the relevant optical quality is evaluated through the proposed ray tracing simulation.