• Journal of Information Display
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• v.13 no.1
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• pp.7-16
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• 2012

In this paper, the problem concerning the color accuracy of imaging systems using color filters is examined. It is shown that the only solution to the problem is to build systems with the spectral response matching the CIE curves as closely as possible. If the spectral response does not closely match the CIE curves, it was demonstrated that calibration cannot solve the problem and will result in very unstable colorimeters. A practical solution that uses telecentric lenses on the sensor side in addition to dedicated color filters for each CCD detector is presented. For systems that closely match the CIE curves, an innovative method of improving the color accuracy based on the precise measurement of the spectral response is presented. The small discrepancies in the spectral response with regard to the CIE curves are corrected in different ways during the measurements. Finally, it is shown that the tristimulus calibration that is used for display measurement is very unstable for systems without CIE matching and is much more stable with systems that closely match the CIE curves.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.31 no.3C
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• pp.264-270
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• 2006

In this paper, we propose the modified display color control system using white point line, boundary lines and S-shaped curves to emphasize blue and red tone colors on CIE1931 diagram. The proposed system divides RGB gamut into movable area and non-movable area by using boundary lines. The colors in movable area are moved into right side or left side along quadratic curve to change the bluish (or reddish) color to more bluish (or more reddish), while those in non-movable area are excepted from color control to prevent skin color from changing. The loci of the quadratic curves are very similar to the arc of the white-point line which connects all points that represent the chromaticities of a black body radiator at different temperatures and is also called the black body locus. The RGB gamut extension by movement of chromaticity coordinate can improve color reproducibility. Therefore in the case of application to LCD, the display shows excellent performance because the LCD's color reproducibility is comparatively lower than that of other display systems. The proposed system is also experimentally demonstrated with Xilinx Virtex FPGA XCV2000E- 6BG560 and the TV set.

• Journal of Korea Multimedia Society
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• v.12 no.5
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• pp.633-643
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• 2009

We propose a color transfer method that used color contrast based templates to express the visual difference clearly between objects, while remaining the quality of the input image. Our algorithm employs colors of both the input image and template distributed on the $a^{\ast}b^{\ast}$chrominance plane of CIE $L^{\ast}a^{\ast}b^{\ast}$color space. The templates are made by considering the effect of color contrast and have the shape of either a line or a curve represented color distribution of the basic colors based gradation image. These tempates can be modeled on spline curves. We also generate simply new templates with the different basic colors by moving the control points of that curve. The color transfer method using the templates is done through a regressive analysis and color matching. We maintained color coherence of the input image by transforming similarly the color distribution of an input image to the one of templates.

• Journal of Korean Ophthalmic Optics Society
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• v.5 no.2
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• pp.157-161
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• 2000

The Eye sensitivity in the difference conditions of a light source intensity consists of two functions by the receptor of cone and rod according to a wavelength. We derived a distribution function of $P({\lambda})=A{\cdot}e^{-({\lambda}-{\lambda}_0)^2/2W^2}$ using a respond probability of the receptor of cone-rod for a photon. It was well applied for a CIE eye's sensitivity curve of a wavelength, we obtained values in case of a relative sensitivity. A = 106.4, ${\lambda}_0=559.2$, W = 83.5 for a photopic and A = 99.3 ${\lambda}_0=502.6$, W = 79.5 for a scotopic, and in case of a sensitivity curve using 1m/W units. $A=7.2{\times}10^4$, ${\lambda}_0=559.2$, W = 83.5 for a photopic and $A=1.6{\times}10^5$, ${\lambda}_0=502.6$. W = 79.5 for a scotopic.