• KSII Transactions on Internet and Information Systems (TIIS)
• /
• v.9 no.6
• /
• pp.2289-2301
• /
• 2015

Mobile devices are becoming powerful enough to realize augmented reality (AR) application. This paper introduces two AR methods to estimate an environmental illumination distribution of a scene. In the first method, we extract the lighting direction and intensity from input images captured with a front-side camera of a mobile device, using its orientation sensor. The second method extracts shadow regions cast by three dimensional (3D) AR marker of known shape and size. Because previous methods examine per pixel shadow intensity, their performances are much affected by the number of sampling points, positions, and threshold values. By using a simple binary operation between the previously clustered shadow regions and the threshold real shadow regions, we can compute efficiently their relative area proportions according to threshold values. This area-based method can overcome point sampling problem and threshold value selection. Experiment results demonstrate that the proposed methods generate natural image with multiple smooth shadows in real-time.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2006.08a
• /
• pp.625-630
• /
• 2006

A new method to get reliable viewing angle measurements on LCD reflective display is presented. This method is based on the use of commercial Fourier optics viewing angle instruments already proposed by ELDIM for more than 15 years. This apparatus is capable to measure simultaneously quasi all the incidence and azimuth angles and to control very precisely the illumination of the sample. We show that, in contrast to other instruments, a clever illumination procedure with two different conditions allows separation of the intrinsic reflective contribution of the display and of the parasitic front end reflection. In this way, intrinsic performances of the display can be obtained at any incidence and azimuth angles and realistic observer conditions can be simulated.

• International Journal of Internet, Broadcasting and Communication
• /
• v.16 no.2
• /
• pp.75-80
• /
• 2024

Research on the visual narrative impact of Unreal Engine's Lumen lighting system in games aims to delve into how Lumen's lighting technology plays a crucial role in game design and gameplay experience, thereby enhancing the visual storytelling of games. Lumen, Unreal Engine's dynamic global illumination solution, calculates lighting and shadows in real-time during gameplay, creating a more realistic and immersive environment. Analysis indicates that Lumen technology not only provides visually realistic and dynamic lighting effects but also significantly enriches the expressiveness and immersion of the game narrative through its changes in light and shadow.

• Proceedings of the Korea Multimedia Society Conference
• /
• 2003.11b
• /
• pp.585-588
• /
• 2003

최근의 영화나 애니메이션에 자주 등장하는 디지털 인간 캐릭터의 제작에서 사실적인 피부 렌더링을 위하여 다양한 공학적, 예술적 접근이 이루어지고 있다. 본 논문에서는 사실적인 피부렌더링을 위해 subsurface illumination 테크닉을 이용한 쉐이더를 구현하고 아티스트들의 효율적인 제어를 위해 보다 직관적인 인터페이스를 제안하였다. 구현한 쉐이더는 3D 그래픽 응용 프로그램인 Maya의 플러그인 형태로 제작되었으며 기존의 전통적인 쉐이딩 인터페이스와의 조화를 고려하여 제안된 매개변수들을 확장 형태로 제공하였다.

• Proceedings of the IEEK Conference
• /
• 2002.07b
• /
• pp.991-994
• /
• 2002

Photon mapping is an efficient global illumination technique for realistic image synthesis that has been developed in computer graphics. In this paper, an adaptive photon mapping in the use of automatic differentiation is proposed. Since the automatic differentiation is used when photons emit from the light sources through the scene, we can check the variation of surrounding shape. Therefore, we can decrease the number of photons and generate an image in relatively low computational cost.

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

• KIPS Transactions on Software and Data Engineering
• /
• v.5 no.12
• /
• pp.677-684
• /
• 2016

For realistic rendering volume to calculate the light effects as well as the shade is essential. In order to produce the high quality of the resulting image, it is necessary to represent a global illumination, and it should be considered an indirect effect of the direct impact and scattering of light. It requires a lot of resources in order to perform this operation and, in particular, is very expensive when large amounts of data to be rendered as a volume data is consumed. In this paper, we generate a scatterer template according to the physical laws for each material. Considering that each object having material property stores photons of the template based on the Lambert illumination model. When the volume rendering in this paper, using the photon is stored in the template, based on the voxel to be sampled within the examination volume occluded, and it represents the global illumination of the scattering. Because the materials produced by the template requires a less resource only if comprised of a complex material, a simple operation can be expressed within the scattering volume at a low cost through.

• Proceedings of the IEEK Conference
• /
• 2004.08c
• /
• pp.862-866
• /
• 2004

Non-intrusive methods based on active remote IR illumination for eye tracking is important for many applications of vision-based man-machine interaction. One problem that has plagued those methods is their sensitivity to lighting condition change. This tends to significantly limit their scope of application. In this paper, we present a new real-time eye detection and tracking methodology that works under variable and realistic lighting conditions. Based on combining the bright-pupil effect resulted from IR light and the conventional appearance-based object recognition technique, our method can robustly track eyes when the pupils are not very bright due to significant external illumination interferences. The appearance model is incorporated in both eyes detection and tracking via the use of support vector machine and the mean shift tracking. Additional improvement is achieved from modifying the image acquisition apparatus including the illuminator and the camera.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.8 no.2
• /
• pp.240-244
• /
• 2007

Non-intrusive methods based on active remote IR illumination fur eye tracking is important for many applications of vision-based man-machine interaction. One problem that has plagued those methods is their sensitivity to lighting condition change. This tends to significantly limit their scope of application. In this paper, we present a new real-time eye detection and tracking methodology that works under variable and realistic lighting conditions. Based on combining the bright-pupil effect resulted from IR light and the conventional appearance-based object recognition technique, our method can robustly track eyes when the pupils are not very bright due to significant external illumination interferences. The appearance model is incorporated in both eyes detection and tracking via the use of support vector machine and the mean shift tracking. Additional improvement is achieved from modifying the image acquisition apparatus including the illuminator and the camera.

• Journal of the Korea Computer Graphics Society
• /
• v.13 no.1
• /
• pp.7-14
• /
• 2007

In this paper we present an illumination model for rendering realistic stained glass. This techniques simulates the phenomenon of stained glass in real world by applying important optical component of the stained glass to the rendering algorithm. The optics for stained glass involves three basic physical mechanisms. First, diffuse light and highlight contribute to the brightness of stained glass which is typically white and changes along with the light source and the view position. Next, Fresnel refraction dominates the amount of refracted (transmitted) light. Finally, we express volume absorption occurs in all stained glass. Then, the rendered stained glass images achieve excellent realism.