• Journal of the Korean Institute of Telematics and Electronics D
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• v.34D no.7
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• pp.62-70
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• 1997

In this paper, the optical conditins of a reflective multi-color STN-LCD based on electrical control of birefringence is designed on the poincare sphere. First of all, the angles of polarizer and analyzer for the best color purity are decided in the configuration without a retardation film. A retardation film is introduced for a bright white in the range of the applied voltage. The sretardation and the angle of the retardation film are also decided on the poincare shpere. The test cell is farbricated and its measured spectral transmittance and the CIE chromaticity diagram agree well with simulations.

• Korean Journal of Optics and Photonics
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• v.10 no.2
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• pp.138-145
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• 1999

By varying the beam current of a color CRT(cathode ray tube) monitor, the misconvergence, spot size, display luminance, and chromaticity coordinate of a white pattern were measured at 4 screen positions. The misconvergence was measured with a linear CCD (charge coupled-device). The resolution was obtained by using SQRI (square root integral) method. The misconvergence of a color monitor was not influenced by the beam current but by the screen position. The misconvergence on a screen perimeter caused the resolution to decrease.

• Journal of the Optical Society of Korea
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• v.18 no.5
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• pp.616-622
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• 2014

Specular structural colors generated by two-dimensional periodic binary gratings are investigated theoretically. An approximate mathematical model of the grating specular structural colors is described, based on scalar nonparaxial diffraction theory, and the functional relationships of specular structural color and structural parameters of gratings are analyzed. Through this, the optimal condition for maximizing the color-representation range in the standard CIE 1931 chromaticity diagram is derived.

• 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).

• Journal of Korea Multimedia Society
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• v.13 no.4
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• pp.535-546
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• 2010

Digital images have undesired color casts due to various illumination conditions and intrinsic characteristics of cameras. Since the color casts in the images deteriorate performance of color representations, color correction is required for further analysis of images. In this paper, an algorithm for detection and removal of color casts is presented. The proposed algorithm consists of four steps: retrieving similar image using color by correlation, extraction of near neutral color regions, kernel density estimation, and removal of color casts. Ambiguities in near neutral color regions are excluded based on kernel density estimation by the color by correlation algorithm. The method determines whether there are color casts by chromaticity distributions in near neutral color regions, and removes color casts for color constancy. Experimental results suggest that the proposed method outperforms the gray world algorithm and the color by correlation algorithm.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.05a
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• pp.131-132
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• 2023

Recently, the construction industry has seen the emergence of interior and exterior finishes using ultra-high performance concrete (UHPC) and colored concrete products using precast concrete (PC). However, the excessive amount of pigment used for coloring reduces the strength of the concrete. There is a need to improve the durability and chromaticity of colored concrete, and further analytical studies on the properties of colored concrete are also required. Therefore, in this paper, colored ultra-high strength cement composites (C-UHSCC) containing red and green inorganic pigments were prepared, and the compressive strength and color of the specimens were measured according to the age, and the correlation between strength and color was analyzed by simple linear regression analysis using R² value. The results showed that the red color was highly correlated with L^* and a^*, and the green color was highly correlated with a^*. These results can be considered for various concrete formulations, but research is needed to suggest the optimal pigment mixing ratio for proper strength and color development.

• Food Science and Preservation
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• v.17 no.2
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• pp.230-235
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• 2010

We investigated the physicochemical quality characteristics of apple juice upon sterilization using hot water, and under various storage conditions. None of sugar content, acidity, or pH differed significantly among various sterilization conditions but chromaticity was considerably reduced in sterilized juice compared with control material. The chromaticity of non-sterilized juice decreased significantly after sterilization compared with material supplemented with vitamin C (0.1%, w/v). Fungi, yeast, and aerobic bacteria were detected in juice sterilized at $65^{\circ}C$ for 10 or 20 min, but no microorganisms were observed in juice sterilized by other procedures. Vitamin C content affected sterilization temperature to a greater extent than sterilization time. When juice was stored at $4^{\circ}C$ or $37^{\circ}C$ for 3 weeks after application of different sterilization conditions, almost no change in acidity, sugar content, or pH was observed, regardless of sterilization mode or storage period. However, chromaticity decreased with longer storage. Vitamin C levels were reduced by higher sterilization temperatures. However, longer storage periods had the greatest effect on reduction of vitamin C levels, which tended toward lower values regardless of differences in sterilization and storage conditions. In sensory evaluation tests, all of taste, color, and overall preference were highest for juice sterilized at $75^{\circ}C$ for 20 min. The ASC value was low at a storage temperature of $4^{\circ}C$ and at high sterilization temperatures, and a long storage period was associated with a greater ASC value. Thus, the quality of apple juice was excellent when juice was hot water-sterilized, with additional vitamin C, at $75^{\circ}C$ for 20 min, followed by storage at $4^{\circ}C$.

• Journal of Korea Multimedia Society
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• v.13 no.5
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• pp.641-650
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• 2010

Color image sensors (CIS) output color images through image sensors and image signal processing. Image sensors that convert light to electrical signal are divided into CMOS image sensor and CCD image sensor according to transferring method of signal charge. In general, a CIS has RGB output signals from tri-stimulus XYZ of the scene through image signal processing. This paper presents an adaptive colorimetric analysis method to obtain chromaticity and luminance using CIS under various environments. An image sensor for the use of colorimeter is characterized based on the CIE standard colorimetric observer. We use the method of least squares to derive a colorimetric characterization matrix between camera RGB output signals and CIE XYZ tristimulus values. We first survey the camera characterization in the standard environment then derive a SGL(shutter-gain-level) function which is relationship between luminance and auto exposure (AE) characteristic of CIS, and read the status of an AWB(auto white balance) function. Then we can apply CIS to measure luminance and chromaticity from camera outputs and AE resister values without any preprocessing. Camera RGB outputs, register values, and camera photoelectric characteristic are used to analyze the colorimetric results for real scenes such as chromaticity and luminance. Experimental results show that the proposed method is valid in the measuring performance. The proposed method can apply to various fields like surveillant systems of the display or security systems.

• Journal of the Korean Graphic Arts Communication Society
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• v.13 no.1
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• pp.13-24
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• 1995

The color filter os made in four methods ; dyeing, printing electrodisposition and pigment dispersed method. Among technologies for color filter manufacture, pigment-dispersed and hybrid method are dominant over all others in commercial manufacture of large scale, fine resolution color filter for liquid crystal display. In this paper to investigate the possibility of the color filter manufacture for LCD by screen printing method, we synthesyzed PVA/sbQ screen emulation for high resolution, estimated image of printed fine pattern and manufactured color filter by screen printing. Results of the study are as follow and found the screen printing method os useful and valid from it. 1. Fine pattern is formed due to photocyclodomerization of -C=C- bond at 342nm, on the other hand unexposured parts are removed in water. 2. sharpness and resolution of fine pattern is improved at mesh streching angle 22.5 and 45 than 0 degree. It is expected due to resistance between inks and mesh streching angles. 3. Spectral characteristics of sample inks were R(640nm), G(535nm), B(470nm), transmittance were R(92%), G(79%), B(70%) and chromaticity coordinate values were R(0.62,0.33), G(0.32,0.59), B(0.14,0.17)

• Journal of Korean Ophthalmic Optics Society
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• v.6 no.2
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• pp.37-46
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• 2001

In this study, We compared the properties of tinted and colored lenses with the standards m the ordinary optical properties, coloration, UV, IR and luminous transmittance, color acceptance for traffic signal, and chromaticity. The UV, lR and luminous transmittance was analysed in the range of 175 nm to 3000 nm by using a UV-Vis-IR spectrophotometer and was used in the synthesis of spectrum of various color lens. A experimental function was made from the slope obtained from the transmittance change as a function of coloration time. We could expect the ordinary optical properties and color acceptance for traffic signal of various color lenses with the requirements of US standard(ANSI Z-80.3).