Takehiro Nakatsue

19.2: xvYCC: A New Standard for Video Systems using Extended-Gamut YCC Color Space

We have developed a new display / video camera and wide-gamut characterizing tools for a new standard for extended-gamut YCC color space called xvYCC. Video systems adapting this standard will have improved accuracy of color reproduction of real world.

Survey of actual viewing conditions at home and appropriate luminance of LCD-TV screens

— To understand actual viewing conditions at home is important for TV design. And the preferred luminance level of LCD TVs under actual viewing conditions is also important in order to obtain both good picture quality and low power consumption. The actual viewing conditions of households and the preferred luminance levels was investigated. In a field test of 83 households, the display luminance, screen illuminance, and viewing locations were measured on site. In laboratory experiments, young and elderly subjects adjusted the luminance of an LCD-TV screen to their preferred levels under different screen illuminance levels, angular screen sizes, and average luminance levels (ALL) of the images. As a result, two equations, which represent the preferred luminance level of LCD-TV screens corresponding to different viewing conditions for young and elderly subjects were obtained. When the ALL of the images was 25% and the screen illuminance and angular screen size were set at 100 lx and 20°, respectively, the preferred luminance was 1 60 cd/m2 for the young subjects and 248 cd/m2 for the elderly subjects. By using the setting of the preferred luminance of an LCD TV under actual viewing conditions, it is possible to conserve energy consumption.

18.2: Distinguished Paper: Appropriate Luminance of LCD‐TV Screens under Actual Viewing Conditions at Home

The preferred luminance level of LCD televisions under actual viewing conditions is important to obtain both good picture quality and low power consumption. We investigated actual viewing conditions of households and preferred luminance levels. As a result, we obtained equations which represent the preferred luminance level corresponding to different viewing conditions.

52.5: Effect of Color Gamut Volume in Display on Image Preference

We measured image preference using paired comparison when varying the color gamut and maximum luminance of the display to investigate the effect of color gamut volume on image preference. There is a trade-off relationship between the area of color gamut and luminance on image preference.

4.1: Color Conversion from Film to xvYCC Video Signal

The color gamut of xvYCC is wider than that of film. We evaluated the color reproduction and developed a new method of converting the video signal, which reproduced color of a film in xvYCC color space faithfully.

67.1: Evaluation of Gamut‐Expansion Algorithms for Wide‐Gamut Display

Different gamut expansion algorithms were applied to sRGB images and evaluated using paired comparison on image preference. Two performed better regardless test scenes. Image preference was highly correlated to lightness contrast, and there is a preferable range in the degree of chroma enhancement.