Moon-Cheol Kim

Optically adjustable display color gamut in time-sequential displays using LED/Laser light sources

Abstract Recently, various wide color gamut displays have been developed. Because of color gamut differences between wide gamut displays and the standard definitions, the color reproduction on such display system is not equal to original images. To overcome this, a color transformation such as gamut mapping algorithm is applied in conventional systems. But this manipulates only the video signal that would reduce the signal dynamic range and produces quantization error of video signal. In this paper, we propose a new optical Color Gamut Processing instead of an image data mapping. In the method, an individual color gamut of the standard definitions can be composed of an optical mixture of original primary colors. As a result, a perfect color match for the various standards can be realized within a display gamut without any signal artifacts. Moreover the same concept is applied to the video stream in order to elevate scene luminance. A scene-adaptive Dynamic Color Gamut Processing measures a color gamut for every video frame and adjusts a matched display color gamut so that it is able to increase display contrast in comparison to conventional display systems.

Study of colorimetric prediction model for DLP PJ TV

The colorimetric model for predicting the luminance and chromaticity coordinates produced by Digital Light Processing (DLP) Projection (PJ) TV has been proposed. A series of test colors were measured. A polynomial function fitted the tone reproduction curves with five coefficients per RGB primary channel. The characterization of neutral color due to the use of spoke light was discussed. Experimental results showed that the proposed method is very effective in the colorimetry in DLP PJ TV.

Study of color reproduction by adjusting picture mode of DLP projection TV

The color characterization of a DLP (digital light processing) PJ (projection) TV is studied by changing the picture modes. After measuring the chromaticity coordinates, luminance, and spectral radiance of red-green-blue and white as a function of the digital-analog convert value, the contrast ratio, white luminance, chromaticity constancy, channel independency are analyzed. And then colorimetric models for producing desired colors on DLP PJ TV are studied. The performances of GOG (gain-offset-gamma) model and 1-D LUT (look up table) model are evaluated by comparing Δ Eab between measured and predicted values for 56 target colors.