• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.29 no.1
• /
• pp.1-8
• /
• 2015

To produce the white light, there are a single chip method using the blue light and phosphor coating, a multi chip method by mixing R, G, B light.. Multi chip method is proper for the smart lighting system by controling color and color temperature. And color rendering of single chip LED is good by even spectral distribution. To apply application technic like smart light system, this paper analyzed the properties of single chip LED and RGB multi chip LED, and implemented the 2 part subject evaluation for single chip LED and RGB multi chip LED. The first part is comparison of properties for single chip LED and RGB multi chip and second part is color appearance evaluation of 8 colors in each lighting environment.

• Journal of Digital Convergence
• /
• v.17 no.4
• /
• pp.255-260
• /
• 2019

This study is about an efficient synthesis of $360^{\circ}$ video and 3D graphics. First, the video image filmed by a binocular integral type $360^{\circ}$ camera was stitched, and location values of the camera and objects were extracted. And the data of extracted location values were moved to the 3D program to create 3D objects, and the methods for natural compositing was researched. As a result, as the method for natural compositing of $360^{\circ}$ video image and 3D graphics, rendering factors and rendering method were derived. First, as for rendering factors, there were 3D objects' location and quality of material, lighting and shadow. Second, as for rendering method, actual video based rendering method's necessity was found. Providing the method for natural compositing of $360^{\circ}$ video image and 3D graphics through this study process and results is expected to be helpful for research and production of $360^{\circ}$ video image and VR video contents.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.18 no.5
• /
• pp.1-8
• /
• 2004

In the present, most lighting simulation programs are based on luminaires data produced at overseas. Currently, it is difficult to use proper domestic luminaire database in most lighting simulation programs, because there are only oversea luminaire database available. Therefore, in this study, domestic luminaire database were developed and categorized, and applied to Internet Web-based RADIANCE rendering system. Luminaire database are constructed with 3D modeling, materials, and IES candlepower distribution data of each luminaire.

• Cartoon and Animation Studies
• /
• s.36
• /
• pp.493-510
• /
• 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 Conservation Science
• /
• v.36 no.4
• /
• pp.236-243
• /
• 2020

In this study, an accelerated aging experiment for fabric and paper was conducted using two light emitting diode(LED) sources with different wavelength characteristics, and the discoloration under each lighting type was examined. Hanji(Korean traditional paper) and related textiles showed more discoloration under blue LEDs, while the blue wool standard showed more discoloration under white LEDs. This, indicated that the deterioration varied depending on the sample color. The the effect of the light source on artifact deterioration was primarily related to the total radiation flux(expressed in mill watts), rather than the total luminous flux(expressed in lumens). In addition, the discoloration of the investigated artifacts was dependent on the color rendering of the lighting.

• Journal of Korea Game Society
• /
• v.7 no.3
• /
• pp.59-66
• /
• 2007

Ray tracing is one of the classical global illumination methods to generate a photo-realistic rendering image with various lighting effects such as reflection and refraction. However, there are some restrictions on real-time applications because of its computation load. In order to overcome these limitations, many researches of the ray tracing based on GPU (Graphics Processing Unit) have been presented up to now. In this paper, we implement the ray tracing algorithm by J. Purcell and combine it with two methods in order to improve the rendering performance for interactive applications. First, intersection points of the primary ray are determined efficiently using rasterization on graphics hardware. We then construct the acceleration structure of 3D objects to improve the rendering performance. There are few researches on a detail analysis of improved performance by these considerations in ray tracing rendering. We compare the rendering system with environment mapping based on GPU and implement the wireless remote rendering system. This system is useful for interactive applications such as the realtime composition, augmented reality and virtual reality.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.17 no.2
• /
• pp.666-671
• /
• 2016

This paper introduces a device providing close local lighting to the affected part, where the operation-purpose astral lamp alone cannot shed light directly, in an operation room of hospitals or clinics, which helps clinical doctors perform safe treatment of the affected part deep inside a human body. This medical assisting lighting is a device necessary to prevent fatal operation failures, which can occur with minute operation processes, such as tumor removal or angiorrhaphy. The components, such as the light source and power supply were designed to be low power consuming and small in size, have a narrow angle lens was used to increase the light spreading effect and focused illumination. The end-caps of the light transmission device using an optical cable and the lighting device were designed in the waterproof type to enable disinfection of these devices after use for the next patients. According to the measurement of the light source properties made after development of the retractor lighting device, the illumination intensity was 490 lux, the brightness was $11,550cd/m^2$, general color rendering index was 78, color temperature was 11,000K, and the intensity distribution was even, which were confirmed to be adequate for medical assisting local lighting.

• Journal of the Semiconductor & Display Technology
• /
• v.16 no.4
• /
• pp.11-15
• /
• 2017

Red phosphors, $Sr_2Si_5N_8:Eu^{2+}$, were synthesized as a single-phase crystal structure by optimizing carbon and $Eu^{2+}$ contents in a carbothermal reduction nitridation method. With increasing $Eu^{2+}$ contents, the photoluminescence spectra were red-shifted from 600 nm peak for 1 mol% for to 700 nm for 7 mol%. It was suggested that this red shift is attributed to the energy transfer from one low-energy sited $Eu^{2+}$ (1) to other high-energy sited $Eu^{2+}$ (2). Finally, the best red sample (620 nm emission peak and 80 nm half width for 3 mole% of $Eu^{2+}$) was packaged on a Blue LED together with two additional green and yellow phosphors, the fabricated White LED showed a high color-rendering index of 90 and white color coordinates of x= 0.321 and y = 0.305.

• Korean Institute of Interior Design Journal
• /
• no.37
• /
• pp.110-118
• /
• 2003

Computer simulation is one of the most useful techniques to predict daylighting performance and present visual image. In architectural and interior design practice, the Lightscape is commonly used often to produce persuasive images rather than physically accurate results. Therefore, this study is to validity the Lightscape as daylighting evaluation tool, in particularly performance and realistically visualization. For the purpose, an evaluation test model (12.0m$\times$7.2m$\times$3.0m) of side lighting window with lightshelf was selected. A 1:6 scale plywood physical model was made. Under clear sky condition, illuminance of 84 Interior point were measured. Lightscape was run on a 750 MHz Pentium PC running Windows 2000 under the same sky condition. And a photography image was compared to rendering image. The physical results of interior illuminance were within 8% between the scale model and Lightscape simulation. There were no differences between the photograph image and rendering image by Lightscape in the sight. Lightscape as visualization tool for daylighting performance was validated.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.23 no.4
• /
• pp.416-422
• /
• 2019

This paper proposes a GPU-based modeling and rendering of 3D clouds using procedural functions. The formation of clouds is based on modified noise function made with fbm(Fractional Brownian Motion). Those noise values turn into densities of droplets of liquid water, which is a critical parameter for forming the three different types of clouds. At the rendering stage, the algorithm applies the ray marching technique to decide the colors of cloud using density values obtained from the noise function. In this process, all lighting attenuation and scattering are calculated by physically based manner. Once we have the clouds, they are blended on the sky, which is also rendered physically. We also make the clouds moving in the sky by the wind force. All algorithms are implemented and tested on GPU using GLSL.