• Title/Summary/Keyword: Lab color difference

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Color Differences of Standard Samples according to Their Lightness Levels (명도 수준에 다른 목표 샘플의 색차)

  • Kim Jeong Ryeol;Lee Seung Jun;Kim Sam Soo
    • Textile Coloration and Finishing
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    • v.17 no.2 s.81
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    • pp.19-25
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    • 2005
  • A colour-difference formulae would be based on a colour appearance model, but, So far, most colour-difference formulae in common use are based on empirical fits to data. Therefore, of the many proposed, none are completely satisfactory but advances have been made in recent years. A new color-difference data set has been produced with the aims of making a comparison of the advanced CIE Lab formulae as well as confirming the effect of color-difference. 416 low lightness pairs that have only lightness-difference were produced for evaluation of CIE Lab-based formulae on lightness-difference from glossy polyester fabric. The standard color-difference pair was prepared and used. It was neutral grey sample pair that has only lightness difference. The standard pair was used to investigate lightness tolerances. And grey-scale method used to evaluate visual assessment. CIE Lab coordinates of the samples were measured using a X-Rite 8200 spectrophotometer. Visual assessments were carried out using Gretag Macbeth The Judge II Light Booth. A study of color tolerances at low lightness was carried out and get avaliable some results.

Investigation of muscle-specific beef color stability at different ultimate pHs

  • Wu, Shuang;Han, Jina;Liang, Rongrong;Dong, Pengcheng;Zhu, Lixian;Hopkins, David L.;Zhang, Yimin;Luo, Xin
    • Asian-Australasian Journal of Animal Sciences
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    • v.33 no.12
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    • pp.1999-2007
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    • 2020
  • Objective: This study was aimed to investigate the muscle-specific beef color stability at normal and high ultimate pHs. Methods: The impact of muscle (Longissimus lumborum [LL] vs psoas major [PM]) and pH (normal ultimate pH [Np] vs high pH dark cutting beef [Hp]) on color stability, indicated by basic color traits, metmyoglobin reducing activity (MRA) and oxygen consumption (OC), as well as the lipid oxidation, were determined over 7 days of display at 4℃. Results: Hp-LL had the highest pH (6.92), followed by Hp-PM (6.01), Np-PM (5.76), and Np-LL (5.52). Hp-LL had increased (p<0.05) a, chroma and % oxymyoglobin during display. Hp-LL also had the highest metmyoglobin (MMb) reducing activity and OC among all the samples, thus, the greatest color stability, although very dark throughout storage, with lowest values for lightness (L) and yellowness (b). Np-LL also exhibited relatively high color stability, as a result of its lower % MMb and OC and higher MRA than psoas muscle samples. The 0.2 unit difference of the pH between Hp and Np psoas muscle, resulted in the difference of the color intensity, not the color stability. Interestingly, high pH psoas muscle (Hp-PM) did not have better color stability than Np-PM, and in fact had lower color stability than even Np-LL. The similar level of OC and lipid oxidation cannot explain the difference in color stability between Hp-PM and Np-LL. Conclusion: The Hp does not always show better color stability compared with Np beef, which depends on the muscle type. The balance of MRA and OC is important to keep the color in great intensity and stability in the meantime.

Comparative study of color reproducibility of zirconia using a dipping method and coating method (도포법 및 침전법을 이용한 지르코니아의 색조 재현성 비교 연구)

  • Lee, Hee-Jung;Kim, Jae-Hong;Kim, Woong-Chul;Kim, Ji-Hwan;Kim, Hae-Young
    • Journal of Technologic Dentistry
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    • v.35 no.3
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    • pp.185-192
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    • 2013
  • Purpose: The aim of this study was to compare with color reproducibility of the coating method and dipping method using a colour liquid. Methods: Two groups of square-shaped specimens ($10mm{\times}10mm$ in diameter, 1.5mm thickness) were prepared for analysis(n=15/group). The CM(Coating Method) group was fabricated as full zirconia specimens with the coating coloring method and Group DM(Dipping Method) was prepared as specimens of 0.7 mm-thick zirconia plate using the dipping coloring method and veneered with 0.8mm-thick porcelain. Color parameters were measured with ShadeEye $NCC^{(R)}$ spectrophotometer and color differences were calculated using the equation ${\Delta}E^*= \{({\Delta}L^*)^2+({\Delta}a^*)^2+({\Delta}b^*)^2\}^{1/2}$. Non-parametric statistical methods, the Mann-Whitney test, and the Kruskal-Wallis test were used to analyze the data. Type one error rate was set at 0.05. Results: Color difference values larger than 7 were observed between specimens with the coating method and the dipping method, which were detectable difference in a clinical setting. Conclusion: Cautious application of the coating coloring method in a clinical setting and further researches to standardize the coating method are needed.

Perceptual Color Difference based Image Quality Assessment Method and Evaluation System according to the Types of Distortion (인지적 색 차이 기반의 이미지 품질 평가 기법 및 왜곡 종류에 따른 평가 시스템 제안)

  • Lee, Jee-Yong;Kim, Young-Jin
    • Journal of KIISE
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    • v.42 no.10
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    • pp.1294-1302
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    • 2015
  • A lot of image quality assessment metrics that can precisely reflect the human visual system (HVS) have previously been researched. The Structural SIMilarity (SSIM) index is a remarkable HVS-aware metric that utilizes structural information, since the HVS is sensitive to the overall structure of an image. However, SSIM fails to deal with color difference in terms of the HVS. In order to solve this problem, the Structural and Hue SIMilarity (SHSIM) index has been selected with the Hue, Saturation, Intensity (HSI) model as a color space, but it cannot reflect the HVS-aware color difference between two color images. In this paper, we propose a new image quality assessment method for a color image by using a CIE Lab color space. In addition, by using a support vector machine (SVM) classifier, we also propose an optimization system for applying optimal metric according to the types of distortion. To evaluate the proposed index, a LIVE database, which is the most well-known in the area of image quality assessment, is employed and four criteria are used. Experimental results show that the proposed index is more consistent with the other methods.

A Quantitative Measure in Uniform Color Space for Dynamic False Contours on PDP

  • Park, Seung-Ho;Kim, Choon-Woo
    • 한국정보디스플레이학회:학술대회논문집
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    • 2002.08a
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    • pp.617-620
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    • 2002
  • Quantitative analysis of dynamic false contours on PDP is essential to evaluate the performance of algorithms for false contour reduction. It also serves as an optimization criterion for selecting the subfield pattern. In this paper, a color difference in uniform color space is defined as a new measure for dynamic false contours. Unlike the measures in previous works, it accounts for the channel dependencies among the RGB color channels.

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A Study on the Conservation of Lady Shim's Costume Excavated in Jecheon Province (제천출토 청송심씨 출토유물의 보존처리)

  • Park, Bong Soon;Lee, Mok Kun;Chang, In Woo
    • Journal of the Korean Society of Costume
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    • v.65 no.7
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    • pp.47-59
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    • 2015
  • This paper studies the conservation treatment of Lady Shim's costume, which was excavated in Jecheon Province in 2012. There were the significant problems, which were encountered in the treatment of the costume ; First the Jeogoris were transformed during the excavation, Second fibers were seriously deteriorated, Third most of the fabrics such as Chusa were readily deformed. To overcome these problems and to secure stability in the conservation treatment, we decided to alternate between two different washing methods ; dry cleaning by n-hexane and wet cleaning by water. The costume shape was recovered by steaming and by swelling with Hanji(Korean traditional paper). The combined cleaning method proved to be relatively efficient and stable. In addition, the shape of Chusa was well preserved by dry cleaning.(using n-hexane also solved the problem of bad smell after washing with organic solvents.) The effects of the conservation treatment on the excavated costumes could be seen in the change of Lab color difference. Washing made the distribution of Lab color difference narrower, which may suggest that the impurities on the fiber was removed by washing. In addition, the value of L was greater than a-value and b-value after the treatment. This result indicates that the change of value represents the change of color difference by cleaning.

The study on the dimensional stability of digitized dental stone replicas according to difference color of gypsum materials (치과용 모형재 색상에 따른 디지털 모형의 체적 안정성 연구)

  • Choi, Seog-Soon;Kim, Ki-Baek;Lee, Gyeong-Tak;Jeon, Jin-Hun;Kim, Jae-Hong
    • Journal of Technologic Dentistry
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    • v.34 no.4
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    • pp.369-377
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    • 2012
  • Purpose: The aim of study was to compare the dimensional stability of digitized dental stone replica using different color of gypsum materials using a white light scanner with three-dimensional software. Methods: A master model(500B-1, Nissin dental product, Japan) with the prepared lower full arch tooth was used. Several type IV stones(white, yellow, green) were used for 30 stone casts(10 casts each) duplicated a master model of mandible. The master model and the replicas were digitized with the non-contacting white light scanner to create 3-dimensional digital models. The linear distance between the reference points were measured and analyzed on the Delcam Copycad$^{(R)}$(Delcam plc, UK) 3D graphic software. One-way analysis of variance(ANOVA) combined with a Tukey multiple-range test were used to analysis the data(${\alpha}$=0.05). Results: There were considerable differences in mean values between gypsum materials within each color(white, yellow, green), and this difference was statistically significant, p=0.001. Conclusion: Digitization of dental materials on optical scanner was affected by color. Three different color of gypsum materials showed clinically acceptable accuracies of full arch digital model produced by them. Besides, these results will have to be confirmed in further clinical studies.

Color Evaluation of Commercial Dehydrated Tea-products by Hunter-Lab Tristimulus Colorimeter (시판차류제품(市販茶類製品)의 Hunter-Lab Tristimulus Colorimeter에 의한 색상(色相) 평가(評價))

  • Park, Kil-Dong;Choi, Jin-Ho;Sung, Hyun-Soon
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.11 no.1
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    • pp.25-30
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    • 1982
  • To evaluate the quality of commercial dehydrated tea-products, the relationships between particle sizes, densities, moisture absorption & desorption and color appearance were studied by using Hunter-lab tristimulus colorimeter and spectrophotometer. Among the tea-products was held no significant relation between particle sizes and color appearance but red ginseng extract powder (RGEP) was included L, a and b values when was reduced particle size. appearance color of tea-products indicated red-orange color, L, a and b values were ranged 32.7 to 48.0, 4.0 to 10.0 and 5.6 to 18.0, respectively, densities of tea-products ranged 0.232 to 0.898 g/ml and increased L values, Hunter's a/b ratio values was included in 0.61 to 0.90. Color stability in this products was well agreed with decrease of total color difference value ($\Delta$E) and chromaticity difference value ($\Delta$C) of the Hunter-lab color data.

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A Study of Onion Skin Pigments in the Extracting Solvents and Residual Pigments after Dyeing the Textiles

  • Bae, Soon-Ei
    • Journal of Fashion Business
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    • v.13 no.3
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    • pp.109-117
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    • 2009
  • To set up the outstanding and scientific dyeing method in making the condensed liquid of pigment obtained from onion skins and the improved reliability, the following basic experiments were performed. The pigment was extracted in the distilled water at $70^{\circ}C$ and methanol at room temperature and then it was analyzed with LC/MS/MS system (Liquid Chomatography/Mass Spectroscopy/Mass Spectroscophy, LIQ Advantage Max, Thermo Finnigan, USA) for its pigmental characteristics. The unrefined silk and refined silk were dyed by making use of the derived pigment in such a way. The chromameter (CR-200, Minolta, Japan) was used to measure the change in surface color in textiles to be dyed by the extracting condition and the color difference ${\Delta}E$ was determined according to the color difference formula CIE LAB through measuring the psychometric lightness L* and chromaticity coordinates a* and b*.

The Effect of Veneering Techniques on the Color Parameters of Y-TZP Based All Ceramic Restoration of Varying Ceramic Core Thickness (지르코니아 코어 두께에 따른 전부도재관의 상부도재 축성방법이 보철물 색조에 미치는 영향)

  • Huh, Sung-Yoon;Son, Ho-Jung;Kim, Hae-Young;Kim, Jae-Hong
    • Journal of dental hygiene science
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    • v.12 no.2
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    • pp.123-129
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    • 2012
  • The aim of study was to compare the color parameters and mean color difference of porcelain specimens by different veneering technique in order to examine the effect of veneering technique on esthetics of yttria-stabilized tetragonal zirconia polycrystalline(Y-TZP) all ceramic restoration. Three groups of square-shaped core ceramic specimens(14mm in diameter and 0.3, 0.5, 0.7 mm) and two groups of veneering ceramic specimen were prepared for analysis. Color parameter($L^*,a^*,b^*$) and color difference of zirconia core squares and core-veneer specimens were measured with ShadeEye $NCC^{(R)}$ spectrophotometer, respectively. Mean color difference(${\Delta}E^*$)were calculated using color difference formula. Two-way analysis of variance(ANOVA) combined with a Tukey multiple-range test were used to analysis the data(${\alpha}=0.05$). ${\Delta}E^*$ values were not significantly affected by core thickness and veneering porcelain(p=0.083). The color differences(${\Delta}E^*$) of core-veneer specimens with 0.5, 0.7 mm-A1,A2,A3.5 shade were mostly below 3.7 which was within the clinically acceptable range, while color differences between 0.3 mm-A1,A2 showed more than 3.7. All-ceramic system has color characteristics that clinicians have to consider when selecting materials. Also, manufacturers of different porcelain systems must make every effort to achieve color reproducibility.