Atmosphere illuminated:the interplay of light characteristics, light perception and atmosphere

How to create the same atmosphere with light anytime anyplac

Visualizing lighting with images : converging between the predictive value of renderings and photographs

Performing psychophysical experiments to investigate lighting perception can be expensive and time consuming if complex lighting systems need to be implemented. In this paper, display-based experiments are explored as a cost effective and less time consuming alternative to real-world experiments. The aim of this work is to better understand the upper limit of prediction accuracy that can be achieved when presenting an image on a display rather than the real-world scene. We compare the predictive value of photographs and physically-based renderings on a number of perceptual lighting attributes. It is shown that the photographs convey statistically the same lighting perception as in a real-world scenario. Initial renderings have an inferior performance, but are shown to converge towards the performance of the photographs through iterative improvements. © (2013) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only

The effect of spatial luminance distribution on dark adaptation

Recent studies show that dark adaptation in the visual system depends on local luminance levels surrounding the viewing direction. These studies, however, do not explain to what extent veiling luminance is responsible for the outcome. To address the latter, in this study dark adaptation was measured for three different spatial luminance distributions surrounding a target to be detected, while keeping the veiling luminance at the location of the target equivalent. The results show that a background with bright areas close to the viewing direction yields longer adaptation times than a background with bright areas at a larger visual angle. Therefore, we conclude that dark adaptation is affected to a great extent by local luminance, even when controlling for veiling luminance. Based on our results, a simple but adequate model is proposed to predict the adaptation luminance threshold for backgrounds having a nonuniform luminance distribution

A comparison of methodologies to investigate the influence of light on the atmosphere of a space

\u3cp\u3eThe impression of a space depends highly on the illumination in the space, which usually is a combination of electric light and daylight. In the present study, we compared three methodologies to study the influence of electric light and daylight on the perception of the light and the perception of the atmosphere of the space. In two experiments, rating scales were used (with a blocked and a random design, respectively) and in a third experiment the paired-comparison method was used to evaluate the light and the atmosphere of the space. In all experiments, visualizations were used to create differently illuminated spaces. All methodologies showed similar effects of daylight and electric light, which attests to the convergent validity of the research methods. However, the methodologies revealed different effect sizes, rendering the paired-comparison design most sensitive to detect the smallest differences. The results also allowed us to explore the contribution of electric light and daylight in creating an atmosphere. The use of visualizations enabled us to control the luminance of daylight and to disentangle the effects of daylight entering a window from the view from a window. The outcomes show that daylight plays a smaller role than electric light on the perception of light and atmosphere in a space when the luminance of daylight is controlled and there is no view outside.\u3c/p\u3

Relation between the perceived atmosphere of a lit environment and perceptual attributes of light

\u3cp\u3eThe impression of a space depends hugely on the light in the space, more specifically on the intensity, colour, beam shape and position of the light sources in that space. This relation though is very complex. The present study aims at understanding the relation between parameters of a lighting design and the resulting perceptions, focusing on the effect that overall brightness and perceived uniformity of the light in the space have on the perceived atmosphere of that space. Employing high-quality visualisations, we found that atmosphere perception can be accurately described by a second-order polynomial as a function of the two perceptual light attributes. In addition, we evaluated how well objective measures reported in literature predict brightness and perceived uniformity.\u3c/p\u3