Comparison of luminance based metrics in different lighting conditions

In this study, we evaluate established and newly developed metrics for predicting glare using data from three different research studies. The evaluation covers two different targets: 1. How well the user’s perception of glare magnitude correlates to the prediction of the glare metrics? 2. How well do the glare metrics describe the subjects’ disturbance by glare? We applied Spearman correlations, logistic regressions and an accuracy evaluation, based on an ROC- analysis. The results show that five of the twelve investigated metrics are failing at least one of the statistical tests. The other seven metrics CGI, modified DGI, DGP, Ev, average Luminance of the image Lavg, UGP and UGR are passing all statistical tests. DGP, CGI, DGI mod and UGP have largest AUC and might be slightly more robust. The accuracy of the predictions of afore mentioned seven metrics for the disturbance by glare lies in the range of 75-83% and does not confirm findings from other studies stating a poor performance of existing glare metrics

Integration of Eye-tracking Methods in Visual Comfort Assessments

Discomfort glare, among different aspects of visual discomfort is a phenomenon which is little understood and hard to quantify. As this phenomenon is dependent on the building occupant’s view direction and on the relative position of the glare source, a deeper knowledge of one’s visual behavior within a space could provide pertinent insights into better understanding glare. To address this need, we set up an experiment to investigate dependencies of view direction distribution to a selected range of brightness and contrast distributions in a standard office scenario. The participants were asked to perform a series of tasks including reading, thinking, filling in a questionnaire and waiting. The direction of their view was monitored by recording participants’ eye movements using eye-tracking methods. Preliminary results show that different facade configurations have different effects on the eye movement patterns, with a strong dependency on the performed task. This pilot study will serve as a first step to integrate eye-tracking methods into visual comfort assessments and lead to a better understanding of the impact of discomfort glare on visual behavior

Indoor thermal and visual well-being of people with autism:preliminary results from a field study in Denmark

The literature contains very little knowledge regarding the indoor well-being of people with autism spectrum conditions (ASC). Though, when dealing with higher autism levels and specific co-morbidities, the lack of autonomy of potential subjects makes standard comfort studies difficult or even impossible. As part of the EU-funded project “SENSEwellbeing”, the present paper shows the preliminary results of a field study on the indoor thermal and visual well-being of non-autonomous people with ASC, performed in a Danish care-center. Due to the fragility of the subjects involved and ethical issues related, we had to overcome several challenges. A determining example is the limited possibility to directly involve the subjects and make interventions in their private spaces in comfort-related experiments. For this reason, the caregivers working in the facility were involved in a semi-structured interview to indirectly characterize the thermal and visual preferences of subjects. Additionally, short- and long-term measurements of indoor quantities were taken in common rooms and empty living spaces. The interviews’ outcomes were linked to the environmental measurement, allowing a preliminary characterization of the adequacy of indoor design in terms of well-being of non-autonomous people with ASC. The study highlights the differences in perception of thermal and visual environment among people with ASC, and the necessity to find solutions to more directly involve non-autonomous subjects in studies on the indoor environment. The present research may also inspire other studies with people with special needs, whose comfort perception would otherwise be challenging to collect

Gaze Responsive Visual Comfort: New Findings On Gaze Behaviour In A Daylit Office Space In Relation To Glare

Using a newly developed gaze-driven methodology for discomfort glare assessments, we studied gaze behaviour in different glare conditions. The study was done in a series of experiments where gaze behaviour of the participants were recorded using eye-tracking techniques and the daylight dynamics were measured using high dynamic range (HDR) imaging techniques. In these experiments 5 daylit and one artificial lighting condition were considered to further our understanding of gaze behaviour in relation to light. Here we present the findings on how gaze behaves in different lighting conditions in relation to glare and task

Cross-validation and robustness of daylight glare metrics

This study evaluates the performance and robustness of 22 established and newly proposed glare prediction metrics. Experimental datasets of daylight-dominated workplaces in office-like test rooms were collected from studies by seven research groups in six different locations (Argentina, Denmark, Germany, Israel, Japan and the United States). The variability in experimental setups, locations and research teams allowed reliable evaluation of the performance and robustness of glare metrics for daylight-dominated workplaces. Independent statistical methods were applied to individual datasets and also to one combined dataset to evaluate the performance and robustness of the 22 glare metrics. As performance and robustness are not established in literature, we defined performance as: (1) the ability of the metric value to describe the glare scale (evaluated by Spearman rank correlation), and (2) the ability of the metric to distinguish between disturbing and non-disturbing situations (evaluated by diagnostic receiver operating characteristic curve analysis tests). Furthermore, we defined robustness as the ability of a metric to deliver meaningful results when applied to different datasets and to fail as few as possible statistical tests. Average Spearman rank correlation coefficients in the range of 0.55?0.60 as well as average prediction rates to distinguish between disturbing and nondisturbing glare of 70?75% for several of the metrics indicate their reliability. The results also show that metrics considering the saturation effect as a main input in their equation perform better and are more robust in daylight-dominated workplaces than purely contrast-based metrics or purely empirical metrics. In this study, the daylight glare probability (DGP) delivered the highest performance amongst the tested metrics and was also found to be the most robust. Future research should aim to optimise the terms of glare equations which combine contrast and saturation effects, such as DGP, PGSV or UGRexp, to achieve metrics that also perform reliably in dimmer lighting conditions than the ones explored in this study.Fil: Wienold, Jan. École Polytechnique Fédérale de Lausanne; SuizaFil: Iwata, T.. Tokai University; JapónFil: Sarey Khanie, M.. Technical University of Denmark; DinamarcaFil: Erell, Evyatar. Ben Gurion University of the Negev; IsraelFil: Kaftan, E.. Ben Gurion University of the Negev; IsraelFil: Rodriguez, Roberto Germán. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Ambiente, Hábitat y Energía; ArgentinaFil: Yamin Garretón, Julieta Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Ambiente, Hábitat y Energía; ArgentinaFil: Tzempelikos, T.. Purdue University; Estados UnidosFil: Konstantzos, I.. University of Nebraska; Estados UnidosFil: Christoffersen, J.. Velux A/s; DinamarcaFil: Kuhn, T. E.. Fraunhofer Institute For Solar Energy Systems; AlemaniaFil: Pierson, Clotilde. Universitee Catholique de Louvain; BélgicaFil: Andersen, M.. Franhofer Institte For Solar Energy Systems; Alemani