• Journal of Korea Game Society
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• v.7 no.4
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• pp.53-62
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• 2007

Although radiosity can represent diffuse reflections of the object surfaces by modeling energy exchange in 3D space, there are some restrictions for real-time applications because of its computation loads. Therefore, GPU(Graphics Processing Unit) based radiosity algorithms have been presented actively to improve its rendering performance. We implement the progressive refinement radiosity on GPU by G. Coombe in 3D scene that is constructed with HDR(High Dynamic Range) radiance map. This radiosity method can generate a photo-realistic rendering image in 3D space, where the synthetic objects were illuminated by the environmental light sources. In the simulation results, the rendering performance is analyzed according to the resolution of the texel in the environmental map and mipmaping. In addition, we compare the rendering results by our method with those by the incremental radiosity.

• Journal of Korea Game Society
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• v.17 no.1
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• pp.7-16
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• 2017

The 3D game graphic technology has become an important factor in the contents field with the game contents development. In particular, game character technology provides a realistic technique and visual pleasure, as well as an intermediate step in the immersion of the game in which the game might create an optical illusion that enables the player to enjoy heroic adventure in the game. The high expression level of characters in 3D games is a key factor in the development process, with details and carefulness of the character setting work [3]. In this paper, we propose a character representative technique applied to mobile games using mathematical model of radiosity energy, spectral radiance model, and ray tracing model method using 3D unity game engine with sensible AI algorithm for game implementation. As a practical application to the game contents, it was found that the projection of the surface in the rendering process and the game simulation might change according to the lighting condition of the game content environment, so that the high quality of game characters was simulated.

• Journal of the Society of Naval Architects of Korea
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• v.55 no.5
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• pp.394-400
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• 2018

Various numerical methods have been adopted for indoor noise assessments of ship plant. Acoustical radiosity method is one of the high frequency approaches for acoustic field analysis, which assumes diffuse reflections by boundaries so that it could be efficiently applied to the acoustically diffused indoor space noise analysis. In this study, an acoustic field analysis program has been developed based on radiosity method, which could apply for acoustically large enclosures such as ship's indoor space. For this purpose, the procedure of the acoustical radiosity method has been summarized and implemented to an acoustic field analysis program using MATLAB. Numerical example for a rectangular indoor space has investigated validity of the implemented program. Steady state sound pressure levels calculated for a continuous acoustic source signal have shown good agreement with those by other solutions such as an analytic solution and a ray tracing method. Instantaneous sound pressure levels calculated for an impulsive acoustic signal have provided the clues of direct/reflected acoustic field and reverberation time.

• Journal of the Society of Naval Architects of Korea
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• v.56 no.5
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• pp.464-471
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• 2019

The acoustic power is a major acoustical characteristic of an underwater vehicle and could be measured in a reverberant water tank. In order to obtain accurate measurement results, the acoustic field formed by the sound source should be investigated quantitatively in the reverberant water tank. In this research, the acoustic field of a reverberant water tank containing an underwater sound source has been analyzed by using an acoustic radiosity method one of the numerical analysis methods suitable for the acoustic analysis of the highly diffused space. The source level of the underwater sound source and acoustical properties of the water tank input to the numerical analysis have been estimated by applying the reverberant tank plot method through a preliminary experiment result. The comparison of the numerical analysis result with that of the experiment has verified the accuracy of the acoustic radiosity method.

• 한국HCI학회:학술대회논문집
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• 2007.02a
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• pp.988-993
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• 2007

전역조명기법(global illumination)중에서 난반사(diffuse reflection) 객체들 사이의 관계를 효과적으로 표현하는 래디오시티(radiosity)방법은 객체들 사이의 에너지 교환에 에너지 평형 상태를 모델링 한다. 그러나 래디오시티는 많은 계산량으로 인해 실시간 활용에는 적합하지 않았다. 최근 장면생성에 걸리는 소요시간을 크게 단축시킬 수 있는 비용대비 고성능의 그래픽스 하드웨어(GPU)를 이용한 방법들이 제안되고 있다. 객체들 사이에서 교환되는 에너지는 래디언스(radiance)로 표현이 가능하며, 이러한 래디언스는 대상 장면에서 취득한 HDR(High Dynamic Range) 영상으로부터 래디언스 맵을 구성해서 얻을 수 있다. 이를 기반으로 대상장면의 조명환경을 구성하면 대상장면의 복잡도와는 별개로 빠르고 사실적인 합성장면을 생성할 수 있다. 본 논문에서는 G. Coombe 등이 제안한 점진적 세분(progressive refinement) 알고리즘을 수정하여 래디언스 맵을 이용할 수 있도록 하였으며, 각 텍셀(texel)설정 및 보간(interpolation) 적용 등에 따른 실험 결과를 얻고 분석하였다. 구현된 방법은 이후 영상기반 재조명과 그래픽스 하드웨어를 이용한 영상합성 기술로 영화, 애니메이션, 가상현실, 게임 등에 다양하게 활용될 예정이다.

• The Journal of the Acoustical Society of Korea
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• v.22 no.1
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• pp.7-13
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• 2003

Numerous investigations have demonstrated that diffused reflection is one of the most important factors in predicting room acoustics by computer simulation. Recent studies have suggested several computational algorithms in order to account for diffused reflections in the ray tracing or beam tracing method. In this study, a computational algorithm for the calculation of diffuse sound reflections in the image method is suggested and a computer simulation system is developed based on the suggested algorithm. The methodology adopted in our computer simulation system is similar to the extended radiosity method, which is developed for the computer graphics. In a real room, sound energy is reflected in a partially diffused manner which results in four reflection combinations: diffuse-diffuse, specular-specular, diffuse-specular and specular-diffuse. In this study, higher order form factor is introduced to handle the four types of reflection combinations so that the partially diffused reflection could be modeled. In this paper, the concept of extended radiosity method is described and the approximate method of calculating higher order form factor is suggested. Finally, the effect of higher order form factors on the simulation of reverberation time is investigated.

• Journal of the Korean Solar Energy Society
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• v.23 no.3
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• pp.93-102
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• 2003

One of the promising optical daylighting systems is light shelf type daylighting system, Two types of lighting performance analysis methods are 1) Ray-Tracing method and 2) Radiosity method. The purpose of this paper is to compare two methods in terms of advantages and disadvantages by further looking at the detail algorithm. Also. model verification with Lightscape simulations has been conducted. Effectiveness of light penetration factor in terms of daylighting factor has been investigated and quantified. In summer time. the performance of the light shelf was twice better than the case without it.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1999.06a
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• pp.15.1-21
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• 1999

Radiosity method is a global illumination model for image synthesis. It computes all energy interactions among diffuse elements in a virtual environment. One of the major drawbacks if its time consuming computation. Existing radiosity algorithms for static scene is difficult to be applicable to dynamic environments. In this paper we proposed an hierarchical scene partition scheme to speedup the link update computations in the dynamic environments. Since the proposed spatial data structure is global, it not only can be used to speedup the culling of non-affected links after geometry change, but also can be used to accelerate the subsequent visibility computation. Several empirical tests are given to show the efficiency of our improved algorithm.

• Proceedings of the Korean Information Science Society Conference
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• 1999.10b
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• pp.562-564
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• 1999

래디오시티 렌더링 시스템에 적합한 모델링을 하는데 있어서 수작업을 비롯한 기존의 여러 방법을 적용해 본 결과, 제작하고자 하는 환경 설정에 많은 어려움을 겪었다. 본 논문은 이러한 문제를 해결하기 위해, 인크리먼털 컨벡스 헐 모델링 기법을 응용하여 시스템을 개발하였다. 이 시스템은 기본 데이터 정보를 입력하면 자동적으로 패치와 엘리먼트가 생성되는 프로그램으로, 물체가 많은 환경이나 곡면을 비교적 쉽고, 고속으로 표현할 수 있었다. 그리고 인크리먼털 컨벡스 헐 알고리즘으로 생성된 환경에, 폼 팩터의 대표적인 세 가지 알고리즘들을 비교.평가 해본 결과 Cubic-Tetrahedron 알고리즘이 가장 효율적이었음을 알 수 있었다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1999.06a
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• pp.195-200
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• 1999

In computer graphics, the modeling and simulation of flames is a challenging problem. In this paper, we propose an approach for the simulation of a fire disaster. We use particle systems to describe the dynamic behavior fire. The illumination of dynamic flame is rendered by progressive radiosity algorithm.