• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 제14회 신호처리 합동 학술대회 논문집
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• pp.677-680
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• 2001

본 논문에서는 컬러 장치들간에 색을 일치시키기 위하여 휘도 대비와 채도 향상을 고려한 원형 색역 사상(circular shape-based gamut mapping)방법을 제안하였다. 서로 다른 장치들간에 색역을 일치시키기 위해 장치 독립적이고 균등 색 공간인 CIELAB값으로 변환하여 색역 사상을 수행하였다. 인간 시각에 상대적으로 민감한 특성을 가지는 휘도 성분을 JND(just noticeable difference)에 기반해 분할하고, 이를 기점으로 색역을 원의 형태로 나눈다. 이렇게 나뉜 색역은 사상의 방향성을 결정하는 기본 단위로 사용되어, 이들 영역을 기점으로 영역 대 영역별 사상 방법을 사용하였다. 제안한 색역 사상 방법을 모니터와 프린터간에 적용한 결과 보다 선명하고 휘도 대비가 높은 영상을 얻을 수 있었다.

• 한국인쇄학회지
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• 제23권1호
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• pp.27-36
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• 2005

Most of flated scanners and digital cameras in prepress process utilize CCD technology. Device calibration and characterization process is needed to transform the device dependent color to the device independent color. ICC profiles for digital input devices encapsulated information relating the device values to CIELAB or CIEXYZ coordinates. The main purposes of this article is to evaluate some of the transformation methods based on ICC proposed device profiles and to propose optimal color transformation method for accurate color imaging in printing process.

• 한국인쇄학회지
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• 제23권1호
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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.

• 한국인쇄학회지
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• 제13권1호
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• pp.39-55
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• 1995

There has been an enormous emergence of imaging systems dedicated to hardcopy and softcopy color-appearance comparisons. Pre-press industry use the CRT as a soft proofing device to preview and aid with color corrections and changes before producing the final printed image. Color DTP system is required an accurate image-matching between CRT-image and printed image. In other to develop the color DTP,CRT calibration and CRT color transform to CIE color system are necessary. In this paper, we described a method CRT color transform to CIELab color system using RGB image raw data. Experimental results show that described method is useful valid of color image matching.

• 전자공학회논문지S
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• 제36S권4호
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• pp.55-69
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• 1999

일반적으로 잉크젯 프린터는 농도에 대해 선형적인 계조재현 특성을 나타낸다. 그러나 인간 시각의 경우 농도에 선형적인 프린터 출력에 대하여 비선형적인 지각반응을 나타낸다. 즉 농도가 큰 패치(patch)에 대해서는 명도나 색차에 대한 변별력이 작으며 농도가 작은 패치에 대해서는 좀 더 예민한 변별력을 갖는다. 따라서 농도에 선형적인 프린터 출력은 시각적인 활성영역을 줄이므로 프린터에서 구별되는 계조의 범위가 좁아진다. 그러므로 본 논문에서는 인간의 시지각 특성과 매우 상관도가 높은 CIELAB 색공간을 이용하여 균등한 명도 변화 및 색차를 나타내도록 하는 프린터 계조재현 알고리즘을 제안한다. 이때 시각적으로 균등한 변화를 나타내는 프린터의 입력값을 찾기 위해 다층 퍼셉트론 신경망(multi-layer perceptron neural network, MLP)을 이용하였다. 신경망의 학습을 위해 계조에 따른 패치를 만들고, 프린터 구동입력신호 및 패치의 측정된 값으로 신경망을 학습하였다. 학습된 신경망으로 선형적인 출력을 내는 프린터 구동신호를 찾고 LUT(look-up table)를 이용하여 프린터 입력 신호를 역으로 보정하였다. 결과, 보정된 프린터의 출력이 선형적인 계조 변화를 보였고 변화가 인지되는 계조의 범위가 늘어났으며 실형상에 대한 실험에 있어서도 우수한 화질을 보였다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2008년도 하계종합학술대회
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• pp.845-846
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• 2008

Multi-scaled retinex algorithm is generally used to enhance the local contrast and remove the illuminant component. However, if the chromatic distribution of an original image is not uniform and dominated by a certain chromaticity, the chromaticity of resulting image depends on the dominant chromaticity of the original image, thereby inducing the color distortion. In this paper, a modified multi-scaled retinex method to reduce the influence of the dominant chromaticity in the image is proposed using a average chromaticity of original image and global illuminant chromaticity. In addition, to compensate saturation, the chroma value of the resulting image is enhanced based on that of the original image in the CIELAB space.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 ITC-CSCC -2
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• pp.987-990
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• 2002

Fine grayscale data exceeding 8 bits per pixel is mapped into the sRGB color space so as to be displayed on a 24-bit sRGB CRT monitor. The characteristics of the pseudo gray generated by mapping are investigated in terms of the CIELAB color difference and chromaticities.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 신호처리소사이어티 추계학술대회 논문집
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• pp.15-18
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• 2003

This paper proposes a color matching 3D look-up table simplifying the complex color matching procedure between a monitor and a mobile display device. In order to perform color matching, it is necessary to process color of image in the device independent color space like CIEXYZ or CIELAB. We improved the S-curve model to have smaller characterization error than tolerance error. Also, as a result of the experiments, we concluded that the color matching look-up table with 64(4$\times$4$\times$4) is the smallest size allowing characterization error to be acceptable.

• Fibers and Polymers
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• 제2권1호
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• pp.157-162
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• 2001

Dyebath used for metal complex dyeing of nylon microfiber was recycled to reduce the overall amounts of metal complex dyeing effluents. Instead of discharging the dyebath after each dyeing cycle, the residual dyebath was analyzed spectrophotometrically and reconstituted to the required concentration of dyes and auxiliaries. Dyebaths were reused eight times and the CIELAB coordinates of dyed samples were measured after each recycling. Color difference($\Delta$E*) between the sample dyed in the fresh bath and that from reused dyebath was maintained below 1.5. The levelness and fastness of dyed fabrics from recycled dyebath were not impaired either. Chromium content of each recycled dyebath was similar to that of the first residual dyebath.

• 한국의류학회지
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• 제13권4호
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• pp.380-387
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• 1989

The Purpose of this study was to investigate the color changes of acid dyed wool fabrics after imparting permanent pleats with si-ro-set finish. Monoethanolamine sulfite was used as a reducing agent. Color changes were determined by measuring CIELAB values after treating the dyed fabrics with various setting temperatures, times and concentrations of MEAS. Setting temperature affected the color changes: in the order of $150^{\circ}C>130^{\circ}C>170^{\circ}C$ Setting time had a tendency to increase the color change. As the concentration of MEAS increased, $\delta$ E was increased. Azo dye was more affected than anthraquinone dye by MEAS treatment. Color changes were mainly due to $\delta$ L.