• Korean Journal of Optics and Photonics
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• v.35 no.3
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• pp.95-106
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• 2024

In the 21st century, white light-emitting diodes (LEDs) are widely used as backlighting for liquid crystal displays and as a light source for general illumination. However, white LEDs used in lighting often use a single yellow phosphor on top of a blue LED chip, which lacks the ability to reproduce natural colors in objects under conventional illumination accurately. Recently, researchers have been actively working on realizing high color-rendering lighting by incorporating red quantum dots to improve the spectrum in the long-wavelength band, which is deficient in conventional white LEDs. In particular, how to develop and apply remote quantum dot components to ensure long-term reliability is currently under active research. This paper introduces recent research on remote quantum dot components and the current status of developing high color-rendering lightings with them. Especially, we focus on various factors that are important to consider in optimizing the optical structure of the quantum dot components and discuss the future directions and prospects of research for high color-rendering lighting technology.

• Journal of the Korea Fashion and Costume Design Association
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• v.6 no.3
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• pp.45-53
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• 2004

Natural dyes have poor colorfastness as a result of the exposure of the dyed fabric to sunlight encountered during the display or wearing. As colors on fabrics fade excessively under sunlight, it is a problem to infer and restore the historic textiles with natural-dyed fabrics to original colors. The object of this study is to analyse the factors affected to color change under light. In experimental, fifteen natural dyes were dyed by the Korean traditional dyeing methods onto natural fiber fabrics: cotton, silk, ramie, and flex. Total 49 dyed fabrics in combination with dyes and fibers were used for the specimen. The Weather-O-meter was used for evaluating the effects of exposure to light for 2.5 to 450 hours. The process of color changes in the CIEL *A*B* color-order system to the exposure time were determined by spectrophotometer at 10$^{\circ}$ observer. Sunlight exposure caused significant changes in the color of natural-dyed fabrics. The degree and nature of color changes on the fabrics were dependent on the combination of fiber and the type of dye used. The groups of violet(Lithospermum erythrorhizon Sieb.et Zucc.) and black color(Ailanthus altissima Swingle, Phus trichocarpa Miq) yielded excellent colorfastness to light. The group of indigo blue color(Polygonum tinctorium Lour.) was also very resistant to fading in both exposure except silk. Whereas the dye groups of Red, Yellow, Orange, Brown colors indicated greatest changes in fading, particularly Carthamus tinctorius L.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.2 no.3
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• pp.79-86
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• 2009

This study proposed a method of detecting the facial area by calculating Euclidian distances among skin color elements and extracting the characteristics of the face. The proposed algorithm is composed of light calibration and face detection. The light calibration process performs calibration for the change of light. The face detection process extracts the area of skin color by calculating Euclidian distances to the input images using as characteristic vectors color and chroma in 20 skin color sample images. From the extracted facial area candidate, the eyes were detected in space C of color model CMY, and the mouth was detected in space Q of color model YIQ. From the extracted facial area candidate, the facial area was detected based on the knowledge of an ordinary face. When an experiment was conducted with 40 color images of face as input images, the method showed a face detection rate of 100%.

• Transactions of the Korean Society of Automotive Engineers
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• v.24 no.2
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• pp.214-224
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• 2016

This paper proposes an algorithm to effectively detect the traffic lights and recognize the traffic signals using a monocular camera mounted on the front windshield glass of a vehicle in day time. The algorithm consists of three main parts. The first part is to generate the candidates of a traffic light. After conversion of RGB color model into HSI and YCbCr color spaces, the regions considered as a traffic light are detected. For these regions, edge processing is applied to extract the borders of the traffic light. The second part is to divide the candidates into traffic lights and non-traffic lights using Haar-like features and Adaboost algorithm. The third part is to recognize the signals of the traffic light using a template matching. Experimental results show that the proposed algorithm successfully detects the traffic lights and recognizes the traffic signals in real time in a variety of environments.

• Textile Coloration and Finishing
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• v.27 no.4
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• pp.288-300
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• 2015

This study was executed to substitute Carbon-arc method, which is a method currently used for testing light-fastness of military textile products, with Xenon arc method. Specimens used in the study were classified according to the fabric material and color of military textile products and were composed of 11 items of 42 kinds with different colors. Light-fatness test was done by comparing the result of Carbon-arc(KS K 0700) and Xenon arc(KS K ISO 105-B02) method. In Xenon arc method, blue wool reference materials of 1~8 was used, and exposure condition preferred in American continent and light exposure method 3 were applied. After testing with both methods, grade of light-fastness, color difference, reflectance and color were examined. Even though there was a slight difference among 42 specimens used in the test, results exceeded the quality standard both in Carbon-arc-lamp and Xenon arc-lamp. Therefore, it was confirmed that applying KS K ISO 105-B02 together in the KS K 0700-regulated Ministry of National Defense standard and purchase order would also fit.

• Journal of Industrial Technology
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• v.39 no.1
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• pp.33-39
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• 2019

This paper addresses effects of nanoscale structures on structural colors of micropatterned transparent substrate by light diffraction. Structural colors is widely investigated because they present colors without any chemical pigments. Typically structural colors is presented by diffraction of light on a micropatterned surface or by multiple interference of light on a surface containing a periodic or quasi-periodic nano-structures. In this paper, each structural colors induced by quasi-periodic nano-structures, periodic micro-structures, and nano/micro dual structures is measured in order to investigate effects of nanoscale and microscale structures on structural colors in the transparent substrate. Using pre-fabricated pattern mold and hot-embossing process, nanoscale and microscale structures are replicated on the transparent PMMA(Poly methyl methacrylate) substrate. Nanoscale and microscale pattern molds are prepared by anodic oxidation process of aluminum sheet and by reactive ion etching process of silicon wafer, respectively. Structural colors are captured by digital camera, and their optical transmittance spectrum are measured by UV/visible spectrometer. From experimental results, we found that nano-structures provide monotonic colors by multiple interference, and micro-structures induce iridescent colors by diffraction of light. Structural colors is permanent and unchangeable, thus it can be used in various application field such as security, color filter and so on.

• Korean Institute of Interior Design Journal
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• no.34
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• pp.114-123
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• 2002

Koreans have regarded the red as a major color from old times. The red is a traditional color to have symbols of high position, national foundation and especially royalty. So, we can see the reds in the palace for kings very much.The purpose of this study is to draw out the features of color red in the Kyungbok palace. The color was analyzed by two categories-architectural buildings${\cdot}$structures and ornamental painted patterns. The major findings from this research are summarized as follows:1. Seokganju(similar to terra rossa) and toyugsaek(light seokganju) are found main colors in architectural space, while seokganju has a linear effect and toyuk has a facial effect. 2. Yugsaek(similar to light vermillion) and Jangdan(similar to orange) are found main colors in ornamental painted patterns. These colors are more vivid and brighter than those for architectural space.3. As for two-color combination, reds and blues(including greens) are found major combination both of architectural space and ornamental patterns. And reds and white are the following combination, which gives an bright image by white. 4. As for three-color combination, red-white-black combination of pediment and red-blue-white combination of openings are found very popular in architectural space, while red-blue-yellow combination is most popular in ornamental patterns.The reds are found dominant color of both architectural space and ornamental patterns in the Kyungbok palace. The color design as shown in the Kyungbok palace can be considered as the feature of traditional color design.

• The Korean Journal of Food And Nutrition
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• v.10 no.2
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• pp.241-245
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• 1997

In order to make natural food color from Gardenia, we investigated optimal conditions of color extraction, and thermal stability and light stability of color extracted compared with Yellow-4. In case of ethanol extraction, optimal conditions for color extraction were substrate 10%, 4$0^{\circ}C$, pH 7.0 and 42rs, respectively. In case of water extraction, optimal conditions for color extraction were substrate 10%, 7$0^{\circ}C$, pH 7.0 and 48hrs, respectively. Extraction yield in the optimal conditions was 75% in ethanol and 63% in water. The thermal stability and light stability of Yellow-4 were both upper 98%, but those of Gardenia yellow color were 62 and 90%, respectively.

• International Journal of Highway Engineering
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• v.15 no.5
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• pp.111-122
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• 2013

PURPOSES : The purpose of this system (Rear Lighting System) is to provide illumination for the driver to operate the commercial vehicle safely after dark in highway, to increase the conspicuity of the vehicle, and especially be suggesting the finest observable improvement method, depending on color and pattern of rear lighting system of truck for midnight highway traffic. METHODS : Rear lightning system as an improving way for forward commercial vehicles lighting the securing sight from human factors and the surrounding environment in midnight driving. For this one, basic materials were collected from the data analysis about many types of problems, and filed investigation for establishing Driving Simulator. also taking statistic test to human volunteers after finding recognizable distance of them. RESULTS : As a result, color with the highest visuality is amber followed by green-red-blue as in order for all road types. Especially almost no difference is found between red and green, also when the light is turn off, recognizable distances is wide difference compared to turn on the light. One more thing about study per pattern, upper and entire lighting have similar recognizable distances, but under lighting shows short distance with difficulty securing sight from medians. And straight section shows similar recognizable distances. By finding visuality improvement method depending on color and pattern of supplement taillight, it is expected to suggest quantitative judgement standard for introducing regulation and improvement of supplement taillight. CONCLUSIONS : Night time vehicle conspicuity to the rear is provided by rear position lamps. this study is showed that the color of light ramp is not important to be safe driving, most important is to turn on the light, recognizable distances is big different compared to turn off the rear light, so when the drivng dark in highway, have to turn on the light for reducing risk.

• IEMEK Journal of Embedded Systems and Applications
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• v.9 no.3
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• pp.145-150
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• 2014

This paper presents an effective vision based method for LED traffic light detection at the daytime. First, the proposed method calculates horizontal coordinates to set region of interest (ROI) on input sequence images. Second, the proposed uses color segmentation method to extract region of green and red traffic light. Next, to classify traffic light and another noise, shape filter and haar-like feature value are used. Finally, temporal delay filter with weight is applied to remove blinking effect of LED traffic light, and state and weight of traffic light detection are used to classify types of traffic light. For simulations, the proposed method is implemented through Intel Core CPU with 2.80 GHz and 4 GB RAM, and tested on the urban and rural road video. Average detection rate of traffic light is 94.50 % and average recognition rate of traffic type is 90.24 %. Average computing time of the proposed method is 11 ms.