• Journal of Korea Society of Industrial Information Systems
• /
• v.15 no.5
• /
• pp.29-35
• /
• 2010

In this paper, We implemented discriminating system for various surround illuminants using photo sensor. To discriminate surround illuminants of display device we implemented discriminating system using photo sensor which has output of Ye and Cy. Experimental results shows that we could discriminate surround illuminants by output voltage ratio (Ye/Cy) of photo sensor in the variable luminous intensity of surround illuminants.

• Journal of Sensor Science and Technology
• /
• v.7 no.6
• /
• pp.409-417
• /
• 1998

Originally, the reference white of the NTSC system used to be CIE illuminant C of 6774K. However, that of color television receiver has been adjusted to 9300K as a result of consumer preference for a very bluish white for monochrome television. Recent studies have revealed that the preferred color temperature of display white should be 3000K or 4000K higher than that of surround illuminant. Therefore it is required to classify ambient lighting source. In this paper, a efficient method that can distinguish the ambient incandescent lamp from fluorescent lamp under television viewing condition is developed using only two color sensors, yellow and cyan. Experimental results show that the proposed method is very useful for the discrimination of ambient lighting source, fluorescent of 6000K and incandescent lamp of 3000K. The system was also tested for mixture of these light sources.

• Journal of the Korean Institute of Telematics and Electronics S
• /
• v.35S no.11
• /
• pp.133-143
• /
• 1998

The viewers primarily watch a television under the surround light source of an incandescent or a fluorescent light. When human visual system has been adapted chromtically under the different surround light, the same chromaticities elicit quite different color appearnaces. Therefore, the corresponding color reproduction is the most suitable objective of a color television system. In this paper, an efficient corresponding color reproduction method based on the chromatic adaptation of human visual system is proposed in which colors in the display have the same appearance as the colors in the original would have had if they had been illuminated by standard illuminant ($D_{65}$). The chromaticities that appeared neutral in human visual system were determined by the Hunt's experimental results of the color adaptation in picture viewing situations and the corresponding chromaticity coordinates of stimuli in chromatic adaptation were obtained by the Bartleson's theory. Also, the corresponding color reproduction is realized by changing the phase and the gain of the demodulation axes in television receiver. Experimental results show that the proposed corresponding color displayed on the television is better than that of the conventional colorimetric color reproduction under the surround light sources.

• Journal of Korea Multimedia Society
• /
• v.13 no.5
• /
• pp.674-683
• /
• 2010

For the purpose of color reproduction under standard viewing conditions, recently, color display devices have developed for the colorimetric color reproduction. However the real viewing condition of color display devices is quite different from that. Therefore, it is very important for reproduced colors viewed under real conditions to match the color appearance under standard situations. There are various models that can be used to reproduce corresponding colors considering the chromatic adaptation of the human visual system. However neutral point or chromatic adaptation for the luminance level is not enough. In this paper, we propose a model that find adapting white points for the variations of the luminance levels under the same illuminant. This model is modeled by the proportion of Euclidian distance for luminance level. It is the adapting white function of the sigmoid type for surround luminance level. In the model, the optimal coefficients are obtained from the Hunt's experimental result. It is applied in the chromatic adaptation model using the neutral point of the various viewing conditions. And the neutral point can be used as the theoretical standard which determines the reference white of the color display devices.