Perception and Representation of Urban Night Lighting Ambiances in Virtual Reality
CIFRE PhD research project with L’Observatoire de la Nuit
Abstract
Urban-lighting projects are often assessed through quantitative standards and energy targets, while their effects on the human experience of the night, biodiversity, and light pollution receive less attention. They are also difficult to discuss with decision-makers when meetings take place during daytime and proposed nocturnal ambiances cannot be experienced directly.
This PhD project develops immersive tools for representing and evaluating urban night lighting. Virtual-Reality simulations, perceptual studies, and photometric models are combined to help stakeholders compare lighting scenarios, understand their environmental effects, and make more informed decisions about sustainable lighting design.
Research challenges
- Perceiving nocturnity — characterize the scene-dependent sense of being at night beyond a simple reduction in brightness.
- Low-light vision — study how mesopic and scotopic visual effects influence the perception of virtual nocturnal environments.
- Representing light pollution — calculate and visualize direct, reflected, and scattered light so that environmental impacts can be considered during the design phase.
- Supporting decisions — develop realistic, schematic, and false-colour representations adapted to the needs of urban-lighting professionals, public authorities, and other stakeholders.
Current research
The project has introduced the concept of nocturnity, defined as the feeling of being at night elicited by a scene. A first 42-item questionnaire organizes this experience into perceptual, activity-related, and inner-state dimensions. Its content was reviewed by urban-lighting experts and is being evaluated through Virtual-Reality experiments and broader image-based studies.
This metric provides a basis for future experiments on the simulation of night vision, including colour desaturation, reduced visual acuity, and luminance shifts. The research also examines physical presence, cybersickness, chronotype, and fatigue as factors that may influence responses to virtual nocturnal scenes.
Industrial developments
Research prototypes are integrated into Obscura, L’Observatoire de la Nuit’s real-time lighting-simulation software. Developments include photon mapping for estimating indirect light, visualisation of photometric distributions, support for architectural DXF plans, and assistance in selecting luminaires for street-lighting renovation. These tools connect quantitative photometric calculations with the qualitative experience of urban night environments.
People involved
PhD student
Academic supervision
The PhD is directed by Myriam Servières at AAU-CRENAU, École Centrale de Nantes, and co-supervised by Étienne Peillard within the INUIT team at Lab-STICC.
Industrial supervision
The research is followed at L’Observatoire de la Nuit by Nicolas Houel, who contributes expertise in urban planning, lighting sobriety, and the design of nocturnal ambiances.
Partners
- L’Observatoire de la Nuit provides the industrial context, lighting expertise, field cases, and the Obscura simulation environment.
- AAU-CRENAU contributes expertise in urban digital models, spatial perception, and the study of architectural and urban ambiances.
- Lab-STICC — INUIT contributes immersive systems, interaction methods, and experimental expertise in Virtual and Augmented Reality.
Publications
Funding
This research project is carried out through a Convention Industrielle de Formation par la Recherche (CIFRE) managed by the French National Association for Research and Technology (ANRT).