Evaluation of Occupants’ Visual Perception in Day Lit Scenes: A Virtual Reality Experiment

Abstract

Daylight improves indoor environmental quality, the physical and mental health of occupants, and their efficiency. Research in the area of human-centric lighting that considers the visual and non-visual effects of light on human vision, have focused on examining human visual perception in response to a wide variety of lighting aspects. To investigate the effect of surface materials, window size, and shading patterns on participants’ evaluation of brightness, daylight distribution, contrast, and satisfaction with view, a virtual reality experiment is implemented in a university classroom. Moreover, responses are compared with metrics (i.e., RAMMG and illumines level) to evaluate their performance and robustness. Thirty-three subjects evaluated thirteen immersive virtual environments (IVEs) with different glazing visible light transmittance, reflectance coefficient of surfaces, window to wall ratio, number of windows, and shading geometry using a Likert-type scale survey. The results indicated that participants’ evaluation of brightness is influenced by reflection coefficient of the surfaces and WWR. While daylight distribution is affected by number of windows and shading geometry in addition to other studied parameters. Based on the subjects’ responses the contrast is only affected by reflection coefficient of the surfaces. Their satisfaction with amount of outside view is also influenced by WWR and number of windows. Moreover, based on statistical results defining a specific range of acceptable contrast based on the RAMMG metric is not suggested, and users' evaluation depends on the surface material in addition to the reflection coefficient of them. Furthermore, the level of lighting perceived by people is affected by materials and their color (beside the reflection coefficient of the surfaces), number of windows (even with similar WWR), and shading pattern (even with the same aperture ratio) as well as the glazing visible light transmittance.