• Title/Summary/Keyword: Color characterization

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Color correction of tile color input device using the Neural Network (신경망을 이용한 칼라 입력장치의 칼라 보정)

  • Eum, Kyoung-Bae;Ahn, Chang-Sun
    • Journal of The Korean Association of Information Education
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    • v.3 no.1
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    • pp.134-142
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    • 1999
  • The demand for recognizing the color as well as the object shape is increasing to use the detailed information, because-the expense of color input/output devices become cheap. The research on the color correction should be researched for the exact color presentation and color reproduction of color input/output systems. In this paper, we researched on the color correction of color scanner. The characterization of color scanner is a two step process of gray-balancing and color transformation. The decoupling of the gray-balancing from the color transformation enables the portability of the scanner characterization. We used the least square methods for the line fitting and the Neural Network for the storage space and computation speed. The output of Neural Network is similar to the target value in three-dimensional tristimulus space. The proposed color correction method can be used for all scanners of a manufacturer's model because of the portability.

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Inverse characterization method for color gamut extension in multi-color printer (색역 확장을 위한 멀티 칼라 프린터의 역 특성화 방법)

  • Jang, In-Su;Son, Chang-Hwan;Park, Tae-Yong;Ha, Yeong-Ho
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.44 no.2 s.314
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    • pp.46-54
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    • 2007
  • In current printer industry, four or more colorants are added for color gamut extension because the gamut of printer is smaller than other devices. However, these additional colorants make a redundancy problem that several combinations of colorants reproduced same color stimulus in colorimetric inverse characterization process. Thus, we propose a method of colorimetric inverse characterization using color correlation between colorant's amount. First, for analyzing the combination of colorants which represent the same color stimulus, we estimate the color stimulus for all combination of colorants by Cellular Yule-Nielsen Spectral Neugebauer printer model. The combination of colorants which has higher color correlation factor comparing combinations of colorant around itself in color space is selected. It can reduced the color difference from the tetrahedral interpolation process which is estimation of the output value(colorants combination) for arbitrary input(color stimulus). The selected combinations of colorants and their color stimulus are stored to the lookup table. In experiment, the CMYKGO printer was used. As a result, the dark region of color gamut was extended and the color tone was more naturally represented.

Flowering, a Critical Phenological Stage as a Limiting Factor for Almond Native Ecotypes Cultivation in Eastern Morocco

  • Melhaoui, Reda;Abid, Malika;Mihamou, Atika;Sindic, Marianne;Caid, Hana Serghini;Elamrani, Ahmed
    • Applied Microscopy
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    • v.47 no.3
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    • pp.157-159
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    • 2017
  • This study concerns (i) Botanical characterization of local almond ecotype named "Beldi" based on flowering period and flowers color measurements (ii) Chemical characterization of almond oil such as acidity and peroxide index and specific UV absorbance values (K232 & K270). The color results of 100 flowers analyzed by chromameter shows two different color categories. The first is very light pink to whitish ($L^*=81.58$, $a^*=7.43$, $b^*=8.06$). The second is a dark pink ($L^*=71.64$, $a^*=18.34$, $b^*=4.97$) with a difference in color between the two categories ${\Delta}E=15.07$. Compared to Ferragnes/Ferraduel varieties, Beldi almond kernel has almost a comparable oil yield but different acidity and peroxide values which are 0.81%, $8.12meq/O_2/kg$ and 0.40%, $16.39meq/O_2/kg$ respectively.

A Study on the Color Reproduction Characteristic of Original Copy in Display Device (디스플레이 장치에서 인쇄원고의 컬러 재현특성에 관한 연구)

  • Cho, Ga-Ram;Koo, Chul-Whoi
    • Journal of the Korean Graphic Arts Communication Society
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    • v.23 no.1
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    • pp.65-75
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    • 2005
  • An accurate characterization of the display device is essential for better color matching. The calibration and characterization process in display device is needed to transform the device dependent color to the device independent color. The process of characterization performs a linearization and transforms the linearized values into the CIE XYZ tristimulus values. The purposes of this paper is to propose optimal color transformation method for accurate reproduction of original copy in display device and to explain the propriety of transformation method using specific variable for the power of gradation expression.

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Implementation of the Color Matching Between Mobile Camera and Mobile LCD Based on RGB LUT (모바일 폰의 카메라와 LCD 모듈간의 RGB 참조표에 기반한 색 정합의 구현)

  • Son Chang-Hwan;Park Kee-Hyon;Lee Cheol-Hee;Ha Yeong-Ho
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.43 no.3 s.309
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    • pp.25-33
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    • 2006
  • This paper proposed device-independent color matching algorithm based on the 3D RGB lookup table (LUT) between mobile camera and mobile LCD (Liquid Crystal Display) to improve the color-fidelity. Proposed algorithm is composed of thee steps, which is device characterization, gamut mapping, 3D RGB-LUT design. First, the characterization of mobile LCD is executed using the sigmoidal function, different from conventional method such as GOG (Gain Offset Gamma) and S-curve modeling, based on the observation of electro-optical transfer function of mobile LCD. Next, mobile camera characterization is conducted by fitting the digital value of GretagColor chart captured under the daylight environment (D65) and tristimulus values (CIELAB) using the polynomial regression. However, the CIELAB values estimated by polynomial regression exceed the maximum boundary of the CIELAB color space. Therefore, these values are corrected by linear compression of the lightness and chroma. Finally, gamut mapping is used to overcome the gamut difference between mobile camera and moible LCD. To implement the real-time processing, 3D RGB-LUT is designed based on the 3D RGB-LUT and its performance is evaluated and compared with conventional method.

EVALUATION OF THE COLOR REPREDUCTION ON LCD MONITORS

  • Park, Seung-Ok;Kim, Hong-Suk;Lim, Yong-Jin;Yang, Jae-Youl
    • Proceedings of the Korean Society for Emotion and Sensibility Conference
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    • 2000.04a
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    • pp.407-411
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    • 2000
  • Color reproduction n CRT monitors needs colorimetric characterization concluding two stages with 3x3 matrix and three TRCs (Tone-Reproduction Characteristics). The 3x3 matrix is based on the additivity of RGB emissions, and the TRC represents the non-linearity between the input digital counts and the output luminance. The objective of this project is to evaluate the accuracy of color reproduction on LCD monitors using conventional CRT model(GOG model). For two different manufacturers, colorimetric characterizations of desktop LCDs have been performed. Because the transfer function for LCD is very differ from TRC of CRT, some researchers had reported that GOG model is inadequate for the colorimetric characterization of LCDs. However in our experiment, the degree of accuracy was dependent on the shape of electro-optical transfer functions of LCD. It has been founded that the GOG model could be applied for LCD monitors having monotonically increased Electro-optical transfer function.

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A Study on Reproduction of Color Image using Gamma Variation on Display Colorimetric Characterization (디스플레이 특성화과정에서 감마변화를 이용한 컬러이미지 재현에 관한 연구)

  • Lee, Sung-Chul;Cho, Ga-Ram;Koo, Chul-Whoi
    • Journal of the Korean Graphic Arts Communication Society
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    • v.23 no.1
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    • pp.1-11
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    • 2005
  • The propose of this study investigated the reproduction of color image on a CRT monitor, for a range of different values of monitor gamma. We have used the GOG(gain-offset-gamma) model of the behavior of CRT. Color difference have been computed in a color space, based on the CIELAB color appearance model. The 133 patch defined linearly color sample and 24 patch defined printing color target were used, and were subjected to the influence of nine different gamma value. The result shows that netural color is increasing the decrease range of luminance black color than white color. These results concern correct in the context display of color reproduction.

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Making of sRGB image through digital camera colorimetric characterization (디지털 카메라 색 특성분석을 통한 sRGB 이미지 생성)

  • 유종우;김홍석;박승옥;박철호;박진희
    • Korean Journal of Optics and Photonics
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    • v.15 no.2
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    • pp.183-189
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    • 2004
  • As high quality digital cameras become readily available, digital cameras are being used not only for simple picture recording but also as information storing media in various fields. However, due to the fact that the spectral responses of the camera sensors are different from color matching functions of the CIE standard observer, the color can not be measured using these cameras. This study shows a method for converting camera image to sRGB image, in which color information is preserved. The transfer matrix between camera output signals and CIE stimulus values was determined using a multiple regression method with Macbeth ColorChecker as target colors. The CIE stimulus values for camera output signals can be mapped with a transfer matrix, and these values are converted to sRGB signals. As the result of testing a Kodak DC220 digital camera, the average color difference of Macbeth ColorChecker between true and displayed colors was 2.1 $\Delta$ $E_{ab}$ $^{*}$.$^{*}$.

Symmetric Bis-Azospiropyrans: Synthesis, Characterization and Colorimetric Study

  • Nourmohammadian, Farahnaz;Abdi, Ali Ashtiani
    • Bulletin of the Korean Chemical Society
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    • v.34 no.6
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    • pp.1727-1734
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    • 2013
  • Synthesis and characterization of some novel symmetric bis-azospiropyrans are reported in this study. These bis-azospiropyrans are bifunctional chromophores with two spiropyrans linked by a bis-azo extended aromatic system that produce more color strength (large molar absorption coefficient in mero forms) due to appending two azospiropyran chromophores on one molecule. Comparing to the molar absorption coefficients of the conventional spiropyran chromophores (${\varepsilon}=0.31{\times}10^4\;M^{-1}{\cdot}cm^{-1}$) and mono-azospiropyran chromophores ($1.35{\times}10^4\;M^{-1}{\cdot}cm^{-1}$), the novel synthesized photochromes showed astonishingly increased molar absorption coefficients ($2.3-3.8{\times}10^4\;M^{-1}{\cdot}cm^{-1}$) at the same conditions. Such high molar absorption coefficients confers high sensitivity to light and more color intensity of mero form, that leads to improvement of their light sensitivity and better discrimination of spiro (OFF) form from mero (ON) ones in molecular switches. The structures were deduced from their MS, FT-IR, and $^1H$-NMR spectroscopic data and CHN analysis. All the synthesized photochemically bifunctional compounds revealed fluorescent emission in their colorless form which was faded out after exposing to UV light. Fluorescence quantum yield values of the mero forms were 0.25-0.81 and two high fluorescence quantum yield values (0.60 and 0.81) were found in these series.