• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1996.06a
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• pp.181-185
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• 1996

Color image is largely corrupted by various ambient illumination. However, human perceives always white color as white under any illumination because of a characteristic of human vision, called color constancy. In the conventional algorithm which applied the constancy effect, after the RGB color space is transformed to the IHS(Intensity, Hue, and Saturation) color space, then the hue is preserved and the intensity or the saturation is properly enhanced. Then the enhanced IHS color is reversely transformed to the RGB color space. In this process, the color distortion is included due to the color gamut error. But in the proposed algorithm, there is not transformation. In that, the RGB color is considered as 3 dimensional color vector and we assume that white color is the natural daylight. As the color vector of the illumination can be calculated as the average vector of R, G, and B image, we can achieve the constancy effect by simply rotating the illumination vector to the white color vector. The simulation results show the efficiency of the vector rotating process for color image enhancement.

• Journal of the Optical Society of Korea
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• v.18 no.6
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• pp.777-782
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• 2014

This paper proposes an RGB to RGBY color conversion algorithm for liquid crystal display (LCD) using RGW pixel structure with two-field (yellow and blue) sequential driving method. The proposed algorithm preserves the hue and saturation of the original color by maintaining the RGB ratio, and it increases the luminance. The performance of the proposed RGBY conversion algorithm is verified using the MATLAB simulation with 24 images of Kodak lossless true color image suite. The simulation results of average color difference CIEDE2000 (${\delta}E^*_{00}$) and scaling factor are 0.99 and 1.89, respectively. These results indicate that the average brightness is increased 1.89 times compared to LCD using conventional RGB pixel structure, without increasing the power consumption and degrading the image quality.

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

• Proceedings of the KIPE Conference
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• 2007.07a
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• pp.244-246
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• 2007

The LCD backlight technique using light-emitting diode(LED) has been studied in the recent backlight market. The white light is need for LCD backlight and it is generally implemented by combining the RGB-LEDs to obtain the high brightness. However, RGB-LEDs have different color characteristics for the current and temperature variations, which results in the color shift problem. The color shift characteristics of RGB-LEDs for the current and temperature variations are investigated in this paper. This result can be used to control the color of backlight system using RGB-LEDs.

• Korean Journal of Optics and Photonics
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• v.30 no.3
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• pp.101-105
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• 2019

An LCD backlight unit (BLU) using RGB light sources is designed and simulated, in order to improve its optical energy efficiency. A color-matching BLU is designed with a lenticular lens array (LLA) with elements that image the linear RGB light sources onto the RGB subpixels of the color filter. Type-A and Type-B simulations are performed, according to the location of the light sources. As a result, the luminance increases to 210% in Type-A and 270% in Type-B respectively. The optimum values for the height and the gap of the LLA for maximum efficiency are found to be $25{\mu}m$ and $3{\mu}m$ respectively.

• Journal of the Korean Graphic Arts Communication Society
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• v.28 no.2
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• pp.117-128
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• 2010

Advancements in digital image have put high quality digital camera into the hands of many image professionals and consumers alike. High quality digital camera images consist originally of raw which have a set of color rendering operation applied to them to produce good images. With color rendering, the raw file was converted to Adobe RGB and sRGB color space. Also color rendering can incorporate factor such as white balance, contrast, saturation. Therefore, in this paper we conduct a study on production of optimum profile considered color rendering in digital camera. To do the experiment, the images were Digital ColorChecker SG target and ColorChecker DC target. A profiling tool was ProfileMaker 5.03. The results were analyzed by comparing in color gamut of $CIEL^*a^*b^*$ color space and calculating ${\Delta}E^*_{ab}$. Also results were analyzed in terms of different $CIEL^*a^*b^*$ color space quadrants based on lightness, chroma.

• Journal of Korea Multimedia Society
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• v.19 no.10
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• pp.1782-1791
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• 2016

Various color spaces such as RGB, HSV, log-chromaticity have been used in the field of person re-identification. However, not enough studies have been done to find suitable color space for the re-identification. This paper reviews color invariance of color spaces by diagonal model and explores the suitability of each color space in the application of person re-identification. It also proposes a method for person re-identification based on a histogram refinement technique and some fusion strategies of color spaces. Two public datasets (ALOI and ImageLab) were used for the suitability test on color space and the ImageLab dataset was used for evaluating the feasibility of the proposed method for person re-identification. Experimental results show that RGB and HSV are more suitable for the re-identification problem than other color spaces such as normalized RGB and log-chromaticity. The cumulative recognition rates up to the third rank under RGB and HSV were 79.3% and 83.6% respectively. Furthermore, the fusion strategy using max score showed performance improvement of 16% or more. These results show that the proposed method is more effective than some other methods that use single color space in person re-identification.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.5
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• pp.1049-1054
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• 2011

Color is discerned due to the reflectance of object and its hue is determined by the Ratio of RGB spectrum. The aim of this study is to evaluate the Color information using by the optical system in terms of convenience and simplicity. Firstly, the differential Ratio of RGB is evaluated by photodiode Sensor which achieves a high efficiency with quick tranducer output. To extract the information of RGB Ratio, light emitting diode is built in Color sensing system with photodiode. Our proposed method is very economical, simple, and convenient. Our results can be applied to confirm the accurate information of Color in the research environments and commercial purposes. Thus RGB information can be determined subjectively and thus, the inherent characteristic of Color will be revealed precisely and its related features can be resolved in a real time mode.

• Journal of Korean Ophthalmic Optics Society
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• v.10 no.1
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• pp.1-8
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• 2005

Color vision of color vision deficiency is possible using Color space's conversion of color image. Color vision of the RG-Color vision deficiency is possible by the case to maximize the G channel(+100), the case to minimize the G channel(-100), the case to maximize the R channel(+100), the case to convert the R channel to the yellow(Y) channel that is the value of $(-)b^*$ coordinate in CIE $L^*a^*b^*$ color space, the case to separate with only the B channel and the G channel and to appear by the light and darkness difference again, and the case to receive the image only by the light and darkness after separation of saturation and conversion of RGB channel.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.1086-1089
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• 2006

We have developed 2.4" QVGA wide color gamut LCD module using RGB-LED backlight. The color gamut is achieved 100% of NTSC compared to 70% of NTSC when used with White-LED backlight. But RGB LED backlight is difficult to maintain its color balance since RGB LED is gradually degraded by the change of ambient temperature and a long term aging characteristic, etc. This paper describes a feasibility study of our optical feedback system developed for preventing such a color shift.