• Applied Chemistry for Engineering
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• v.21 no.5
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• pp.559-563
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• 2010

The representation of color with natural dyes is closely related with the modern well-being life. This study is focused on the representation of target color of the blue, yellow, and red color system, these color sources were originated from the green tea, gardenia, and black rice respectively. The quantitative numerical value of brightness (L), color coordinates (a, b) were designated for the target color, the optimum color nearest to the target value was extracted with the solvent pH, temperature, and extraction time. The longer the extraction time had more thickening color in case of the gardenia. The L-a-b coordinate of extracted color were analyzed with the color difference meter and compared with the target color. The experimental variables were optimized to extract the color of the smallest ${\Delta}E$ with the target color. As a result, the CIE standard value was proposed and the color was represented.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.04a
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• pp.25-26
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• 2008

In this paper, the white organic light-emitting diode(OLED)was fabricated using the DPVBi of blue emitting material and a rubrene of orange color of fluorescent dye by vacuum evaporation processes. The device structure of OLED was Glass/ITO/2T-NATA(15nm)/NPB(3nm)/DPVBi(3nm)/DPVBi rubrene[2%](10nm)/DPVBi(25nm)/$Alq_3$ or New-ETL(60nm) /LiF(0.5nm)/ Al(100nm). The device with the $Alq_3$, layer shows orange color, and the luminance of 1000cd/$m^2$ at an applied voltage of 10.4V. On the other hand, the New-En layer results in white color, CIE coordinates of (0.327, 0.323), and the lowered driving voltage of 5V for achieving the same luminance value.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.10 no.2
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• pp.54-62
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• 1996

A multichannel type spectroradiometer which can measure the optical characteristics of light sources was constructed. Our system can be used to measure the optical characteristics of light sources of which the wavelengths are ranging from ultraviolet to infrared(220nm~1100nm)in 16msec. The optical characteristics such as color coordinates, color rendering index, brightness, color difference, etc. was measured and analyzed.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.25 no.1
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• pp.1-8
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• 2011

In this paper, the method to calculate chromaticity coordinate from spectral power distribution of LED is presented. Also, inverse tri-stimulus algorithm to find mixed luminance of red, green, blue LED from targeted luminance and chromaticity coordinate is proposed. Besides, digital light color control system of LED lamp applied this algorithm has been developed. In experiments, each chromaticity coordinate of red, green, blue LED calculated from this algorithm has relative percentage error of few % to measured values. Digital code is drawn from inverse tri-stimulus algorithm, and measured values of luminance and chromaticity coordinate of LED lamp digitally controlled by this code also have relative percentage error within a few % to targeted luminance and chromaticity coordinate.

• Journal of Multimedia Information System
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• v.1 no.1
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• pp.1-10
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• 2014

In this paper, we propose a new view synthesis technique for coding of multi-view color and depth data in arbitrary camera arrangements. We treat each camera position as a 3-D point in world coordinates and build clusters of those vertices. Color and depth data within a cluster are gathered into one camera position using a hierarchical representation based on the concept of layered depth image (LDI). Since one camera can cover only a limited viewing range, we set multiple reference cameras so that multiple LDIs are generated to cover the whole viewing range. Therefore, we can enhance the visual quality of the reconstructed views from multiple LDIs comparing with that from a single LDI. From experimental results, the proposed scheme shows better coding performance under arbitrary camera configurations in terms of PSNR and subjective visual quality.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.697-699
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• 2009

Optical properties of white organic light-emitting devices (WOLEDs) fabricated utilizing a phosphor layer acting as a color conversion layer were investigated. The WOLEDs were achieved due to the enhancement in the color conversion efficiency of the phosphor layer, and the chromaticity coordinates of WOLEDs were (0.29, 0.33).

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.48 no.1
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• pp.68-75
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• 1999

Machine recognition of faces from still and video images is emerging as an active research area spanning several disciplines such as image processing, pattern recognition, computer vision and neural networks. In addition, human face identification has numerous applications such as human interface based systems and real-time video systems of surveillance and security. In this paper, we propose an algorithm that can identify a particular individual face. We consider human face identification system in color space, which hasn't often considered in conventional in conventional methods. In order to make the algorithm insensitive to luminance, we convert the conventional RGB coordinates into normalized CIE coordinates. The normalized-CIE-based facial images are KL-transformed. The transformed data are used as the input of multi-layered neural network and the network are trained using error-backpropagation methods. Finally, we verify the system performance of the proposed algorithm by experiments.

• Restorative Dentistry and Endodontics
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• v.23 no.1
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• pp.223-235
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• 1998

The recognition of the esthetics as well as their function of the teeth in the dental field is growing. Evaluating the esthetics of a tooth concerns shape, texture, and color. And among these, color has been the most difficult element to make natural expression. Color is a very subjective element affected by many different factor like light source, object, observer. Numerous efforts to quantifying color has been made. Currently the use of colorimeter and spectrophotometercolor that the color measuring device has been suggested. In this study, the normal range of the tooth color in canines, lateral incisors and central incisors for Koreans was evaluated with a modified spectrophotometer for intraoral use. The color differences in terms of teeth positions, age and area within the tooth was evaluated and comparatively analyzed. Results were as follow ; 1. In all age groups, the central incisors are most bright and least yellowish opposit to the canines are most dark and yellowish. The central incisors and lateral incisors showed the similar color patterns. 2. In the comparison between gender, it showed that in the 10' s group male have more yellowish, the 20's female have lighter and more redness, the 30's indicated more redness in female and in the 40's the lightness is more in female. 3. With aging, there was no significant change in $L^*$ and $a^*$ coordinates but a shift was in $b^*$ to yellowish in the 30' sand 40's in central incisors. Lateral incisors and canines showed a lighter and more yellowish tooth color with an irregular change of color coordinate in $a^*$. 4. In all teeth the middle and cervical portion showed close correlation with over 0.7(0.05>p) but color ($a^*$, $b^*$) showed higher correlation than lightness($L^*$). 5. It has been shown that through the regression test the cervical color could be calculated by the middle color value.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.1
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• pp.99-107
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• 2014

In this paper, a landmark based localization system using a Kinect sensor is proposed and evaluated with the implemented system for precise and autonomous navigation of low cost robots. The proposed localization method finds the positions of landmark on the image plane and the depth value using color and depth images. The coordinates transforms are defined using the depth value. Using coordinate transformation, the position in the image plane is transformed to the position in the body frame. The ranges between the landmarks and the Kinect sensor are the norm of the landmark positions in body frame. The Kinect sensor position is computed using the tri-lateral whose inputs are the ranges and the known landmark positions. In addition, a new matching method using the pin hole model is proposed to reduce the mismatch between depth and color images. Furthermore, a height error compensation method using the relationship between the body frame and real world coordinates is proposed to reduce the effect of wrong leveling. The error analysis are also given to find out the effect of focal length, principal point and depth value to the range. The experiments using 2D bar code with the implemented system show that the position with less than 3cm error is obtained in enclosed space($3,500mm{\times}3,000mm{\times}2,500mm$).

• Applied Chemistry for Engineering
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• v.29 no.3
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• pp.283-288
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• 2018

As the use of environmentally friendly and non-disease natural pigments grows, various methods for extracting natural pigments have been studied. The natural color was extracted from parsley, a vegetable ingredient containing natural dyes. Target color codes of green series of natural dyes extracted as variables #50932C (L = 55.0, a = -40.0, b = 46.0) were set with the pH and temperature of extracted natural color coordinates (of the extracted), and the quantitative intensities of natural dyes were analyzed. During the colorimetric analysis predicted by the reaction surface analysis method, a color coordinate analysis was conducted under the optimal conditions of pH 8.0 and extraction temperature of $60.9^{\circ}C$. Under these conditions, predicted figures of L, a, and b were 55.0, -36.3, and 36.8, respectively, while actual experimental ones confirmed were 69.0, -35.9, and 31.4, respectively. In these results, the theory accuracy and actual error rate were confirmed to be 73.0 and 13.8%, respectively. The theoretical optimization condition of the color difference (${\Delta}E$) was at the pH of 9.2 and extraction temperature of $55.2^{\circ}C$. Under these conditions the predicted ${\Delta}E$ figure was 12.4 while the experimental one was 13.0. The difference in color analysis showed 97.5% of the theoretical accuracy and 4.5% of the actual error rate. However, the combination of color coordinates did not represent a desired target color, but rather close to the targeted color by means of an arithmetic mean. Therefore, it can be said that when the reaction surface analysis method was applied to the natural dye extraction process, the use of color coordinates as a response value can be a better method for optimizing the dye extraction process.