• Journal of the Korean Crystal Growth and Crystal Technology
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• v.18 no.4
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• pp.146-154
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• 2008

This study was carried out for the purpose of obtaining the basic data for color identification of amethyst by spectrophotometer. For this, the eleven amethyst stone and one citrine stone from eight countries were prepared in facet cut or plate. The transmittance and reflection of this samples were investigated as a function of wavelength. The transmittance or reflection was transformed to tristimulus value (X, Y, Z) and chromaticity value (x, y, z) and then compared with the results of eye observation which was plotted on cm xyY color space. Finally, the influence of the amethyst's thickness on transmittance or reflection was investigated.

• Restorative Dentistry and Endodontics
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• v.22 no.2
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• pp.769-781
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• 1997

The tristimulus values of 180 extracted maxillary and mandibular anterior teeth were measured by colorimeter. And it were colnverted to Munsell color order system(Hue, Value, Chroma) and CIE $L^*a^*b^*$ color coordinates. The commonly used Vita, and Bioform shade guides, 2 composite resin shade guides(Prisma APH and Z-100), and a glass-ionomer shade guide(Fuji II) were compared with these teeth. At the middle facial surface, color distributions of teeth were Hue(0.56YR to 9.77Y), Value(2.46 to 7.9), and Chroma(0.14 to 2.02). And the aberaged values and standard deviations for $L^*a^*b^*$ were $63.18{\pm}10.44$, $1.11{\pm}1.66$, and $5.79{\pm}2.36$. The shade guide did not match well with the color space of the human teeth. Especially, the lacks of the Yellow-red Hues and higher values were prominent. Compare with other measurements, the Hues of the teeth measured in this study were broadly distributed(most of ranges in Y and YR were included), while the Value and chroma were shown to the lower.

• Journal of the korean academy of Pediatric Dentistry
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• v.44 no.1
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• pp.1-10
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• 2017

The present study aimed to evaluate the validity of resin infiltration in improving color stability after tooth whitening. Enamel samples were extracted from 40 healthy bovine upper incisors, and primary staining and whitening were performed. After that, specimens were randomly divided into 3 groups : resin infiltration group (n = 15, RI group), resin adhesive group (n = 15, RA group), and control group (n = 10). Secondary staining was performed on all samples. Coloration was assessed 5 times as follows: initial color, immediately after staining, after whitening, after resin application, and after secondary staining. Color was measured using a spectrophotometer and recorded by using the CIE $L^*a^*b^*$ color space. The color changes after primary staining for the RI, RA, and control groups were $12.16{\pm}3.50$, $12.16{\pm}3.38$, and $15.81{\pm}6.39$, whereas those after secondary staining were $15.21{\pm}7.19$, $15.93{\pm}4.31$, and $26.62{\pm}17.89$. Color changes after secondary staining showed a significant difference between the RI and control groups. In the within-group comparison between primary and secondary staining, there was no significant difference found in the RI group only (p = 0.26). The results suggest that Color stability after tooth whitening can be improved using resin infiltration.

• Economic and Environmental Geology
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• v.47 no.6
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• pp.563-569
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• 2014

Ruby is one of the most favor colored gem, for beautiful red tone, be high in scarcity value. However, rubies with high quality are produced in restricted regions, such as in Thailand, Sri Lanka, Myanmar, and Tanzania etc., and they have been gradually exhausted by mining for a long period. Therefore, improving qualities of low level rubies with various treatments is arising an alternative way to obtain better rubies. Gemological and mineralogical properties of the natural ruby from Tanzanian were studied with heat treatments. Those characteristics were compared between only heat and adding flux materials under heating. Tanzanian raw rubies were applied a heat treatment ($1,600^{\circ}C$ for 6 hours). However, chromameter and UV-Vis analyses found that a simple heat treatment is inappropriated for the Tanzanian ruby. Although $Cr^{3+}$ containing for red color in the ruby increased with heat treatment, the ruby displays dark medium red because of Fe in the ruby as a form of $Fe_2O_3$. The low transparency after heat treatment is attributed to the recrystallization of $SiO_2$ which has a low melting point. Chromameter confirmed adding Pb-containing flux under heating greatly improves the clarity and color of Tanzanian rubies with micro-fractures and cavities on the surface. EMPA results show that Pb as an additive fills the cavities and cracks on raw Tanzanian rubies during the heat treatment. As a rewult of it, the quality of the Tanzanian ruby raw dramatically improved. These results indicate that the heat treatment with an additive (Pb in this study) is an effective way to obtain better quality of the Tanzanian ruby. Consequently, this study suggests a suitable method to improve the properties of the Tanzanina ruby. The result of this study would provide useful information to upgrade the qualities of similar gem stones such as corundum and sapphire.

• Food Science and Preservation
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• v.20 no.6
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• pp.760-765
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• 2013

The image analysis as a tool for evaluation of browning degree on fresh-cut lotus root was studied. The fresh-cut lotus root treated as 4 groups (Cont-without any treatment, DB-blanching at $50^{\circ}C$ for 5 min in distilled water, AB-blanching at $45^{\circ}C$ for 5 min in 1% ascorbic acid, CB-blanching at $45^{\circ}C$ for 5 min in 1% citric acid). The samples treated with each methods were packaged with 0.04 mm polyethylene bag ($25cm{\times}30cm$) and stored at $4^{\circ}C$ for 9 days. On the RGB color space, the AB and CB group showed high R, G, B value. On the HSV and CIE $L^*a^*b^*$ color space, the AB and CB group showed low browning area, $a^*$, $b^*$ value and high $L^*$ value. Polyphenol oxidase activity was low in the AB and CB groups in all storage period. This result means that the AB and CB groups were inhibited the development of tissue browning. The result of sensory evaluation also supported this opinion. And the correlation coefficient between sensory evaluation with all color values was over 0.84. Especially, the $L^*$ value showed the highest correlation coefficient (0.93). In conclusion, the image analysis is suitable for analysis of browning degree on fresh-cut lotus root by analyzing diverse color value.

• The Journal of Internal Korean Medicine
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• v.36 no.3
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• pp.348-360
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• 2015

Objectives From observing the tongue of a patient, one can assess the health status; this method has been frequently used in traditional Korean Medicine (KM) clinics. In particular, KM posits that the color of the tongue is highly related to digestive functions. In this study, the color of tongue and heart rate variability (HRV) were compared between chronic dyspepsia (CD) patients and healthy subjects. Methods Healthy subjects and CD patients with functional dyspepsia (FD), gastroesophageal reflux disease (GERD), or chronic gastritis (CG) were enrolled for the study. Profile view images of the tongue were acquired by using a computerized tongue image acquisition system (CTIS). The color of the tongue body was extracted from the non-coated region on the tongue images. Results Color differences in CIE L*a*b* color space between the three sub-types of CD patients and healthy subjects were analyzed by using multiple linear regression analysis with age and sex as the factors. The variable b* was significantly lower in GERD patients than in the controls (p=0.017). Variable a* was significantly lower in CG than in the controls (p=0.03). No significant difference was seen between FD and controls. In GERD, the tongue body seems to be intense red in color; in CG, pale red. Frequency domain analysis showed that HF was significantly lower in GERD patients than in the controls (p=0.041). Conclusions The color of the tongue body and HF of HRV can be used for diagnosing digestive functions in health care.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.5
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• pp.132-140
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• 2016

In this paper, we propose boundary-preserving stereo matching method based on adaptive disparity adjustment using confidence region detection. To find the initial disparity map, we compute data cost using the color space (CIE Lab) combined with the gradient space and apply double cost aggregation. We perform left/right consistency checking to sort out the mismatched region. This consistency check typically fails for occluded and mismatched pixels. We mark a pixel in the left disparity map as "inconsistent", if the disparity value of its counterpart pixel differs by a value larger than one pixel. In order to distinguish errors caused by the disparity discontinuity, we first detect the confidence map using the Mean-shift segmentation in the initial disparity map. Using this confidence map, we then adjust the disparity map to reduce the errors in initial disparity map. Experimental results demonstrate that the proposed method produces higher quality disparity maps by successfully preserving disparity discontinuities compared to existing methods.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.11
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• pp.6-17
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• 2015

In this paper, colors of broadcast lightings composed of Red, Green, and Blue LED(Light Emitted Diode) can be linearly and quantitatively controlled in low illuminance. Because LED cannot emit uniform illuminance in low illuminance, the colors of RGB LED are unmixable. Furthermore, the illuminances are nonlinear with the dimming values of the RGB LED due to the nonlinearity of the output illuminance with the current through the LED. This nonlinearity generated errors of the target colors and illuminances. The proposed algorithm set up the target colors, which is expressed by the color coordinates in CIE 1931 color space, and the target illuminances. Then the illuminances of RGB LED were calculated using color mixing theory. The calculated illuminances determined the dimming values of the RGB LED for transmission via DMX512 communication. After the broadcasting lighting received the dimming values of the RGB LED via DMX512 communication,.RGB LED can emit target color and illuminance, and be controlled by calculating the PWM(Pulse Width Modulation) duty ratio of the hybrid LED driver which be considered the nonlinearity for the illuminances of the LED. As a result, the proposed algorithm can linearly and quantitatively control the colors and illuminances in full range of illuminance. Then we verify experimentally that the errors of the emitted color coordination x, y and illuminance are 2.27%, 3.6% and 1.5%, respectively.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.9 no.3
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• pp.1155-1172
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• 2015

In this paper, we propose a novel saliency detection framework based on illumination invariant features to improve the accuracy of the saliency detection under the different light conditions. The proposed algorithm is divided into three steps. First, we extract the illuminant invariant features to reduce the effect of the illumination based on the local sensitive histograms. Second, a preliminary saliency map is obtained in the CIE Lab color space. Last, we use the region growing method to fuse the illuminant invariant features and the preliminary saliency map into a new framework. In addition, we integrate the information of spatial distinctness since the saliency objects are usually compact. The experiments on the benchmark dataset show that the proposed saliency detection framework outperforms the state-of-the-art algorithms in terms of different illuminants in the images.

• Proceedings of the KIEE Conference
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• 1998.11c
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• pp.776-778
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• 1998

Electrical and optical characteristics of Powder type EL display(P-ELD) in this study are described, In experimental results of V-J, current are increased with increasing the frequency and voltage. Luminance was increased with frequency. This is due to the positive space charge formed to cathode region. Lumiance at 150V, 20 kHz has $840\;cd/m^2$. This tendency is due to the decrease of capacitive reactance in insulator layer. Uniformity of P-ELD shows 97%. CIE chromaticity with increasing frequency are shifted toward blue color. It can be explained in tenn of the difference of recombination energy.