• Cartoon and Animation Studies
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• s.36
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• pp.493-510
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• 2014

From game consoles to TV and Hollywood films, 3D rendering technology is involved in various fields. Up until the late 90s, the computer image rendering method was rasterization that mainly used Phong Shading, and up until recently it was the go-to method for movies and film animation. In the 21st century, the quality provided by Ray Tracing and the development of Global Illumination was much more realistic and thus became popularized. However, despite its growing use in architectural rendering to the markets, Global Illumination in film animation and movies was limited due to its long render time. So, in this thesis, if one were to take the concept from each rendering method and consider it from a mathematical perspective, one could adapt the Ambient Occlusion's equation to the illumination loop equation used in rasterization. This algorithm modification has the capability to reflect the lighting of a diverse array of colors, like in Global Illumination, with a fast render time, as in rasterization, and the example RenderMan Shader is based upon this new algorithm. In conclusion, with Global Illumination's naturalistic lighting and rasterization's rendering speed, the combination of the best points of each is a new method with a short rendering time while producing good quality. I hope animations and films can benefit from this algorithm by the reduction of budget with an overall better quality output in VFX production.

• Journal of Information Processing Systems
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• v.17 no.4
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• pp.737-753
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• 2021

As the demand for high-quality rendering for mixed reality, videogame, and simulation has increased, global illumination has been actively researched. Monte Carlo path tracing can realize global illumination and produce photorealistic scenes that include critical effects such as color bleeding, caustics, multiple light, and shadows. If the sampling rate is insufficient, however, the rendered results have a large amount of noise. The most successful approach to eliminating or reducing Monte Carlo noise uses a feature-based filter. It exploits the scene characteristics such as a position within a world coordinate and a shading normal. In general, the techniques are based on the denoised pixel or sample and are computationally expensive. However, the main challenge for all of them is to find the appropriate weights for every feature while preserving the details of the scene. In this paper, we compare the recent algorithms for removing Monte Carlo noise in terms of their performance and quality. We also describe their advantages and disadvantages. As far as we know, this study is the first in the world to compare the artificial intelligence-based denoising methods for Monte Carlo rendering.

• Journal of KIISE:Computing Practices and Letters
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• v.16 no.2
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• pp.186-200
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• 2010

In order to render global illumination realistically, we need to accurately compute the direct and indirect illumination that represents the light information incoming through complex light paths. In this process, the indirect illumination at given point is greatly affected by surrounding geometries. Harmonic mean distance is a mathematical tool which is often used as a metric indicating the distance from a surface point to its visible objects in 3D space, and plays a key role in such advanced global illumination algorithms as irradiance/radiance caching and ambient occlusion. In this paper, we analyze the accuracy of harmonic mean distance estimated against various environments in the final gathering and photon mapping methods. Based on the experimental results, we discuss our experiences and future directions that may help develop an effective harmonic mean distance computation method in the future.

• Journal of Korea Multimedia Society
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• v.18 no.2
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• pp.158-167
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• 2015

This study presents a new method to improve the speed of high quality volume rendering. We improve the speed of ambient occlusion which is one of the global illumination techniques used in traditional volume visualization. Calculating ambient occlusion takes much time because it determines an illumination value of a sample by integrating opacities of nearby samples. This study proposes an improved method for this by using local statistics such as averages and standard deviations. We calculate local statistics for each volume block, a set of nearby samples, in pre-processing time. In the rendering process, we efficiently determine the illumination value by assuming the density distribution as a normal distribution. As the results, we can generate high quality images that combine ambient occlusion illumination with local illumination in real time.

• Solar Energy
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• v.11 no.1
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• pp.3-15
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• 1991

In this study global radiation and global illumination are directly measured and diffuse radiation and diffuse illumination measured utilizing semi-circular shadow ring. By analyzing measured radiation data, clear and overcast sky are classified according to the sky classification method used in Mantes, France. Measured illumination data are analyzed and 1) Clear sky illumination on a horizontal surface as a function of solar altitude. 2) Overcast sky illumination on a horizontal surface as a function of solar altitude, 3) Monthly variation of illumination. 4) Cumulative percentage of illumination, 5) Daylight intensity as a function of hours in a typical day, 6) Average number hours per day of illumination above 10 and 20klx are presented as a climatic data for daylighting design for Seoul, Korea.

• Journal of The Korean Digital Architecture Interior Association
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• v.5 no.1
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• pp.9-16
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• 2005

In Interior design, light is the most important factor in deciding color, texture and illumination level which are the basic factors of spatial design. To apply rendering technologies on prediction of illuminating effect, it is important to understand and analyse the basic properties of the illumination models that are local illumination model and global illumination model. The illumination models in computer graphics express the factors which determine the surface color, texture and light distribution through the reflection. The purpose of this study is to propose the best way of shading algorithm in interior space provided by the computer, based on the experimental analysis that 5 shading methods are applied to the interior space. The results of this study were as followed. 1) Local illumination models that are Lambert shading, Ground shading and Phong shading are not suitable to the prediction of interior illumination effect. 2) Ray tracing that is global illumination model could be adopted to interior illumination effects. Ray tracing is a very versatile algorithm because of the large range of lighting effects it can model. 3) Neither radiality nor ray tracing offers a complete solution for simulating all interior illumination effects. 4) Radiosity excels at rendering diffuse-to-diffuse inter-reflections and ray tracing excels at rendering specular reflections. By merging both shading techniques, that offers the best of both. Using computer technologies to simulate lighting in preliminary design stage which will provide information for designers and occupants to determine the effect of using artificial light sources at each stage of their design process. Further study in illumination analysis, prediction of illumination effect, and lighting calculation is required as computer media expands.

• 한국HCI학회:학술대회논문집
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• 2008.02a
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• pp.414-419
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• 2008

3D rendering is a critical process for a movie production, advertisement, interior simulation, medical and many other fields. Recently, several effective rendering methods have been developed for the photo-realistic image generation. With a rapid performance enhancement of graphics hardware, physically based 3D rendering algorithm can now often be approximated in real-time games. However, the high quality of global illumination, required for the image generation in the 3D animation production community is a still very expensive process. In this paper, we propose a new rendering method to create photo-realistic global illumination effect efficiently by harnessing the high power of the recent GPUs. Final gathering routines in our global illumination module are accelerated by programmable graphics hardware. We also simulate physically based light transport on a ray tracing based rendering algorithm with photon mapping effectively.

• Journal of the Korea Computer Graphics Society
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• v.26 no.1
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• pp.7-15
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• 2020

In the process of visualizing a point set representing a smooth manifold surface, global illumination techniques can be used to render a realistic scene with various effects of lighting. Thanks to the continuous demand for ray tracing and the development of graphics hardware, dedicated GPUs and programmable pipeline for ray tracing have been introduced in recent years. In this paper, real-time global illumination rendering is studied for a point-set model using ray-tracing GPUs. We apply the moving least-squares (MLS) method to approximate the point set to a smooth implicit surface and render it using global illumination by performing massive ray-intersection tests with the surface and generating shading effects at the intersection point. As a result, a complicated point-set scene consisting of more than 0.5M points can be generated in real-time.

• Journal of Korea Multimedia Society
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• v.12 no.9
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• pp.1262-1272
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• 2009

In computer graphics, there exist many studies about illumination and radiance for a realistic description of the 3D modeling and rendering. When we see a scene, the scene is lit by a source of light and the radiance of the points by a source in the scene. The radiance has direct light and glight component. The direct light gets lights directly from light source, but the global light gets lights indirectly by interreflections among complicated geometrical components. In this paper, we studied a method for increasing the accuracy of separating direct light and global light components from a scene by using high frequency illumination pattern. For experiments, we applied the separating method of Nayar's and found the best configurations for the separation through the experiments. We improved the separation accuracy of direct and global light by measuring the value of unilluminated area, which depends on the characteristics of object. Furthermore, we enhanced invisible scene of the global light by applying the image filtering technique.

• Journal of Korea Game Society
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• v.16 no.2
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• pp.111-118
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• 2016

Global illumination is key factor for realistic image but it is not common in realtime rendering due to its complexity. Visibility of $2^{nd}$ lights is hard to determine because we should process all object for each $2^{nd}$ light. In this paper, we reuse visibility of static objects. We present an indirect illumination algorithm which shows good performance and provides exact $2^{nd}$ light visibility when the scene has small number of moving objects. Our method renders correct image while showing good performance.