Effects of ambient illumination conditions and background color on visual performance with TFT-LCD screens

This study investigated the effects of ambient illumination conditions (illumination color and illumination intensity) and background color on visual performance (character identification and reading comprehension) with TFT-LCD screens.Results of Experiment 1 indicated that all the three independent variables had significant effects on mean percentage of character identification. Mean character identification performance was best under white light, 500 lux, and blue background. In general, the backgrounds with primary colors had better mean character identification performance than the middle-point colors and gray. Results of Experiment 2 indicated that the illumination intensity and background color had significant effects on mean text comprehension performance for reading comprehension. Mean text comprehension performance were higher under 500 lux and blue background. The backgrounds with primary colors had better mean correct answers than the gray background. According to the results, white light, normal ambient illumination and a background with primal colors seemed to be the optimal conditions. If the yellow ambient light is necessary, using blue as the TFT-LCD background color of will provide better performance.The Pearson product-moment correlation coefficient indicated that short-term visual task measurement might be suitable to evaluate the visual performance.     

General framework for measuring the optical characteristics of displays under ambient illumination

A measurement and analysis framework is described that allows a generalized treatment of display ambient performance. The proposed methodology considers the reflection and transmission properties of the display in order to evaluate its on‐screen characteristics under arbitrary illumination conditions. New transmission methods and metrics are developed to compliment the traditional reflection methods. The utility of this framework is demonstrated by evaluating the photometric and colorimetric qualities of an LCD and OLED transparent display for a wide range of ambient lighting environments.     

Effects of contrast and ambient illumination on visual discomfort of autostereoscopic display

The conflict between vergence and accommodation is the main perceptual factors contributing to visual discomfort when viewing autostereoscopic display. The key factors relevant to the accommodation and vergence are the ambient illumination and the contrast. The current study was a 2 × 3 × 3 mixed design comparing VFSI and VIMS symptoms between 2D and 3D video clips with three contrast levels under three ambient illumination levels on the autostereoscopic display. Twenty participants were required to evaluate the degree of discomfort by filing out questionnaires after watching those video clips. According to the result analysis, the 3D viewing participants reported more severe symptoms compared to 2D. The moderate contrast conditions were found to be the optimum for viewing comfort. The difference between VFSI and VIMS symptoms become larger with increasing contrast. The results also suggested the optimum 3D illumination condition should not be too high to effectively relieve visual discomfort. VIMS symptoms were more sensitive to the changes in ambient illumination than VFSI. Moreover, significant interaction between contrast and ambient illumination was found. Participants felt the most comfortable in the combination effect of moderate level of contrast and the high level of ambient illumination.     

Effects of illumination conditions on preferred viewing distance of portable liquid‐crystal television

This study explored the effect of TV size, light source, and ambient illumination on the preferred viewing distance of portable liquid‐crystal‐display televisions. Results showed that the mean preferred viewing distance was 1389 mm. TV size had significant effects on preferred viewing distance. The larger the screen size, the greater the preferred viewing distance, at around 6.7–14.7 times the width of the screen (W). Light sources revealed no significant effect on preferred viewing distance. The effect of ambient illumination on preferred viewing distance was significant. The higher the ambient illumination was, the longer the preferred viewing distance.     

Psychophysical generation of matching images for cross‐media color reproduction

Abstract— A technique was developed and tested for generating CRT pictorial image reproductions that match the color appearance of print originals. Five observers, experienced in using Adobe Photoshop? to adjust images, matched two scenes using a memory‐matching technique. Observers were able to produce accurate matches when originals and reproductions were viewed at the same white point. Observers then matched the reproductions at 6500 K to originals viewed at 9300 and 3000 K. These matches were compared to the predictions of various color‐appearance models, using a paired‐comparison technique in a psychophysical experiment using different observers. The observer‐matched images were found to be equal or superior to matches produced using any of the models.     

A method for selecting display primaries to match a target color gamut

Abstract— A method for selecting primaries of a wide‐gamut display is proposed, in which display color gamut is designed to match a target color gamut in CIELAB color space. A standard deviation of the relative maximum chroma of display and target color gamuts is defined. The selection method optimizes display primaries for the minimum standard deviation so that display and target color gamuts are similar in shape. It is shown that the color gamut of a laser display designed by this method is similar in shape to the theoretical maximum, or optimal, color gamut of objects. It is also shown that the color gamut of an LED display can be designed to include 99.7% of the gamut of Pointer's real‐world surface colors. LED primaries are selected to minimize the standard deviation of the relative maximum chroma of effective display color gamut and a target color gamut which is defined to include Pointer's real‐world surface colors. For both the laser and LED displays, it is necessary to constrain the red‐primary wavelength to avoid excessive optical power for the red primary.     

A novel spectrum‐sequential display design with a wide color gamut and reduced color breakup

Abstract— The advantage of RGB color‐sequential displays is that they have no color filters, but the disadvantage is that they need to run at high refresh rates (> >180 Hz) to prevent flicker and color breakup. An alternative color‐sequential display, which can operate at relatively low refresh rates (～ 100 Hz) without disturbing color breakup or flicker, has been developed. The display has two color filters per pixel (cyan and magenta) on the LCD panel and the backlight can generate two types of spectra (blue‐green and green‐red), which results in a wide gamut four‐primary display, effectively. One part of the paper describes the color reproduction, including color‐filter design, gamut mapping, and multi‐primary conversion. The other part deals with the reduced perception of color breakup on the novel spectrum‐sequential display compared to conventional color‐sequential displays.     

Improving content visibility for high‐ambient‐illumination viewable display and energy‐saving display

Abstract— Nowadays, low‐contrast viewing of LC displays (LCDs) occurs very often, which includes the viewing of mobile LCDs at high ambient illumination and the viewing of LCDs at low‐power mode. These cases result in low‐content visibility and low contrast, leading to an unpleasant viewing experience. In this paper, a technique to improve the perceived contrast and visibility of images at low‐contrast viewing conditions is proposed. The proposed approach enhances image brightness with content and ambient adaptive image brightening and highlights visual parts and boundaries with non‐photorealistic rendering. The proposed technique enables longer battery life for mobile LC devices and makes mobile LC devices viewable at high ambient illumination. It also enables TVs with extreme low‐power consumption and smart‐grid responsive TVs.     

An effective way to achieve full color cholesteric liquid crystal displays with single liquid crystal mixture and layer

Two‐step ultraviolet exposure method to achieve flexible color cholesteric LCD with single liquid crystal mixture and layer was proposed. The first step for polymer wall formation via photo‐polymerization induced phase separation and second step for color rendering with the photo‐sensitive chiral dopant were independently carried out without the interference of ultraviolet reaction using proper band‐pass filer. This display has good color performance and mechanical stability, which can be also driven by simplified driving circuit so that it would be a substantive solution for color flexible displays.     

An introduction to the Information Display Measurement Standard 1, the first display measurement standard from the International Committee for Display Metrology

On June 1, 2012, the Information Display Measurement Standard version 1 was released. This is the first standard from the worldwide standard group, the International Committee for Display Metrology, a standards committee within SID, and it culminates several years worth of development from many contributors at various levels. It has 26 top‐level chapters and a total over 450 sections of all parts, including over 200 measurement sections and 8 appendices that cover 133 topics of display metrology, tutorials, technical discussions, and references. Herein is an overview of the Information Display Measurement Standard version 1, including the structure of the document, tips, tricks, and hidden features, how it is maintained, support material, a breakdown of its contents, and finally, a sampling of four of the over 200 measurements. The standard is available as a free download and can be found on the International Committee for Display Metrology home page — http://www.icdm‐sid.org .