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A psychophysical experiment was carried out to investigate visual comfort when reading on three mobile displays at three luminance levels (100, 250 and 500 cd/m2) at five illuminance levels (0, 10, 100, 500 and 1000 lx). Sixty observers including 20 children, 20 young people and 20 elderly people evaluated visual comfort of 42 text‐background combinations using a six‐category point's method. Various effects of lightness contrast, lightness of background, display luminance, and ambient illuminance on visual comfort for the three age groups were revealed. Most interesting, visual comfort is strongly affected by lightness contrast and different ages. A second‐order polynomial regression model is developed to predict visual comfort based on the display settings and ambient illumination at different ages. It could be a valuable tool to design or evaluate display interfaces. [ABSTRACT FROM AUTHOR]

The purpose of this study was to investigate the perception of neutral white and chromatic adaptation on a display under ambient lighting conditions with different chromaticities and illuminance levels. The desktop display was arranged to simulate a mobile phone. The neutral white was the whitest point that excluded chromatic color. Only one original image was used and it comprised black text against a white background under CIE illuminant D65 and the CIE 1964 standard colorimetric observer. Forty‐two rendered images were made to cover a representative area of chromaticity space that might be considered white. Eleven ambient lighting conditions were applied with five values of correlated color temperature (3000, 4000, 5000, 6000, and 8000 K) each at two illuminance levels (500 and 1000 lx) plus a dark condition. A psychophysical experiment was conducted where observers were asked to judge each image in terms of "neutrality" under each ambient lighting condition. The results showed that there were significant differences between different ambient lighting conditions. All the available data including the present were used to develop an incomplete chromatic adaptation function with different scaling factors for the incomplete adaptation factor (D) in CAT02. The function suggests that the illuminance and chromaticity of the illuminant had a clear trend on chromatic adaptation. However, the degree of adaptation is affected by the viewing conditions in each experiment. [ABSTRACT FROM AUTHOR]

We investigated observer metamerism under a variety of viewing conditions, in a set of color-matching experiments using displays and printed color samples under specific light sources. A selection was made of light sources with different illuminances, spectral power distributions, and correlated color temperatures, as well as displays with different sets of primaries. A panel of 157 observers with normal color vision and ages between 20 and 59 years old performed 5465 visual color matches around 9 different color centers. The results from the simulated and real experiments were quite different. Specifically, the mean color difference from the mean changed with experimental viewing conditions, ranging from 0.73 to 1.64 CIELAB units (average 0.99 CIELAB units) in simulated experiments, and from 3.12 to 4.03 CIELAB units (average 3.55 CIELAB units) in real experiments. In real experiments, observers' variability reduced for light sources with high illuminance and high correlated color temperature. Spectral power distributions affected observer metamerism, but the role played by the primaries of the two displays employed was unclear. [ABSTRACT FROM AUTHOR]

This article describes an experiment carried out to evaluate discomfort glare of nonuniformly distributed light emitting diode (LED) sources. The glare sources were created with a 4 × 4 LED panel. Twenty participants evaluated 140 lighting conditions consisting of eight nonuniformity patterns, four to five levels of luminous intensity, two levels of background luminance, and two angles above the line of sight. Some clear trends were found: discomfort glare was greater when the light source was less uniform and with higher LED luminous intensity, darker background, or a smaller angle above the line of sight. The unified glare rating (UGR) model for small glare sources (UGRsmall) was tested using the experimental data. Although the UGR model had good correlation with visual results, it underestimated perceived glare. In addition, the degree of uniformity of the glare source was found to influence the performance of UGRsmall. As nonuniformity increases, the performance of UGRsmalldecreases. Three modified versions of UGRsmallwere derived, where each of the proposed models better predicts discomfort glare from nonuniform raw LED glare sources. [ABSTRACT FROM AUTHOR]

This paper aims to successfully reproduce a real lit environment as an image on a self-luminous computer display. The International Commission on Illumination-recommended color appearance model CIECAM02 was used as the core of the whole reproduction system. Two experiments were conducted: to verify the values of the surround parameters specified in CIECAM02 and to produce equal perceived brightness between the room and the computer display by adjusting the illuminance level of the lighting in the room to match that of the displayed image. [ABSTRACT FROM AUTHOR]

This paper aims to successfully reproduce a real lighting environment onto a display. The CIE recommended colour appearance model CIECAM02 was used as the core of the whole system. Two experiments were conducted: to verify the surround parameters in CIECAM02 and to establish the relationship between different illuminances between two viewing fields. [ABSTRACT FROM AUTHOR]

Recent studies reported a series of neutral loci for white lighting, which showed significant differences when the correlated colour temperature was greater than 4000 K. Several were located above the Planckian locus while others were located below. In addition, some researchers indicated that the whiteness of lighting correlates with colour preference (i.e. visual appreciation on the colour rendition of lighting) but that conclusion is not in full accordance with certain individual results of preference or whiteness evaluation. To investigate the perceived whiteness and colour preference in a viewing cabinet, two visual experiments were carried out. The light sources adopted in both the experiments were eight sources of 5500 K, that included four with constant positive Duv values (~0.004) and four having constant negative Duv values (~− 0.006). The illuminance levels were approximately 200 lux while the Color Rendering Index (CRI) values were in range of 85–91. The results showed that sources of negative Duvs obtained higher values of whiteness assessment and their colour rendition was preferred by observers. The findings also strengthen the opinion that, for practical conditions with a constant CCT and acceptable CRI values, the Duv value could be considered as an effective indicator for colour preference judgement. • Light sources with moderately negative Duvs were perceived to be whiter. • Light sources with moderately negative Duvs were preferred for colour rendition. • Duv value is effective for colour preference judgement for practical condition. [ABSTRACT FROM AUTHOR]