Outdoor lighting supports human safety and visibility but also contributes to light pollution, which may disrupt ecological systems. This study applies an eco-centric lighting perspective, investigating the integration of three complementary lighting measurement methods using cubic light field measurements, vertical and horizontal illuminance, and luminance mapping. Three luminaire configurations, a conventional 4000 K road luminaire and two 2200 K alternatives (with and without louvre), were examined under varying environmental conditions (clear, cloudy, snowy clear and snowy cloudy). Measurements were conducted along a transect extending from the road into the adjacent terrain. Our findings demonstrate that, when combined, the three measurement methods capture both the spatio-directional spread and diffuseness qualities on the pavement together with the distal effects of the lighting. Horizontal and vertical illuminance measurements revealed that the alternative luminaires reduced spill light into the terrain by up to 45 % compared to the conventional luminaire, with a further 16.6–19.5 % reduction achieved using a louvre. Cubic light field measurements quantified the spatial characteristics of light, showing that light vector magnitude declined rapidly within 3–4 m from the luminaire, and diffuseness drastically changed under snowy conditions with an increase of 112 %. Luminance mapping illustrated differences in contrast and relative visibility between luminaire types; overall, the conventional luminaire tended to stand out more against the background sky. This integrative approach enables a more nuanced understanding of how artificial lighting interacts with the surroundings and may contribute to the development of more eco-centric lighting strategies.

Perceived acoustic environments, or soundscapes, of intensive care units (ICUs) can be stressful for patients. We developed an approach to enhance ICU soundscapes with soundscape interventions. Compositions of Natural, Human, or Technological sounds were designed to establish three types of sonic ambiances: Comfortable, Pleasurable, or Stimulating. The objective was to investigate the approach's effectiveness in a real-world ICU environment. In a controlled experiment conducted in a single-patient, sound-proofed ICU room, 26 healthy participants were exposed to simulated ICU soundscapes, including patient monitor alarm sounds and mechanical ventilator sounds. Nine soundscape interventions were played via speakers. Perceived pleasantness and eventfulness of resulting soundscapes and experienced pleasure and arousal of listeners were evaluated with questionnaires. Physiological indicators of stress were measured using electrocardiograms (ECGs). Pleasurable and Stimulating interventions significantly increased perceived pleasantness and eventfulness when introduced to the simulated ICU soundscape. Comfortable interventions had no significant effect, suggesting that Pleasurable and Stimulating ambiances better aligned with participants’ needs relative to the simulated soundscape. It emphasized the need to tailor ICU interventions to the preexisting acoustic environment and sound-related needs of listeners, such as comfort, distraction or reassurance. Participants reported positive emotional states while listening to the soundscape interventions, indicative of positive listener experiences. Preliminary insights regarding changes in heartrate variability hinted that soundscape interventions could potentially contribute to reduced stress levels. The effectiveness of interventions depended on their featured sound categories, highlighting the importance of personalization. Overall, our approach was found effective, showing promise for creating listener-centric, restorative soundscapes during ICU stays.

The spectral shape, irradiance, direction, and diffuseness of daylight vary regularly throughout the day. The variations in illumination and their effect on the light reflected from objects may in turn provide visual information as to the time of day. We suggest that artists' color choices for paintings of outdoor scenes might convey this information and that therefore the time of day might be decoded from the colors of paintings. Here we investigate whether human viewers' estimates of the depicted time of day in paintings correlate with their image statistics, specifically chromaticity and luminance variations. We tested time-of-day perception in 17th- to 20th-century Western European paintings via two online rating experiments. In Experiment 1, viewers' ratings from seven time choices varied significantly and largely consistently across paintings but with some ambiguity between morning and evening depictions. Analysis of the relationship between image statistics and ratings revealed correlations with the perceived time of day: higher "morningness" ratings associated with higher brightness, contrast, and saturation and darker yellow/brighter blue hues; "eveningness" with lower brightness, contrast, and saturation and darker blue/brighter yellow hues. Multiple linear regressions of extracted principal components yielded a predictive model that explained 76% of the variance in time-of-day perception. In Experiment 2, viewers rated paintings as morning or evening only; rating distributions differed significantly across paintings, and image statistics predicted people's perceptions. These results suggest that artists used different color palettes and patterns to depict different times of day, and the human visual system holds consistent assumptions about the variation of natural light depicted in paintings.

The light field describes the light in a given space, capturing spatial and form-giving visual qualities of light, such as the direction and diffuseness, in addition to conventional intensity-related metrics. In urban mobility, this is connected to social aspects, as these lighting qualities impact how objects or people appear. We tested how these lighting qualities vary objectively, optically, in real conditions and whether they influence a social factor like the subjective, perceived friendliness of a face, and how well-lit a face and surroundings appeared. The results showed that how well-lit, friendly, and comfortable faces and environments were rated, did not correlate to light intensity. The results instead indicated the importance of factors related to the modelling effects of the lighting like diffuseness and light vector.

We present a method to capture the 7-dimensional light field structure, and translate it into perceptually-relevant information. Our spectral cubic illumination method quantifies objective correlates of perceptually relevant diffuse and directed light components, including their variations over time, space, in color and direction, and the environment’s response to sky and sunlight. We applied it “in the wild”, capturing how light on a sunny day differs between light and shadow, and how light varies over sunny and cloudy days. We discuss the added value of our method for capturing nuanced lighting effects on scene and object appearance, such as chromatic gradients.

Chromatic properties of the effective light in a space are hard to predict, measure and visualise. This is due to complex interactions between materials and illuminants. Here, we describe, measure and visualise the effects of inter-reflections on the structure of the physical light field for diffusely scattering scenes. The spectral properties of inter-reflections vary as a function of the number of bounces they went through. Via a computational model, these spectral variations were found to be systematic and correspond with brightness, saturation and hue shifts. We extended our light-field methods to measure and understand these spectral effects on the first-order properties of light fields, the light density and light vector. We tested the model via a set of computer renderings and cubic spectral illuminance measurements in mock-up rooms under different furnishing scenarios for two types of illuminants. The predicted spectral variations were confirmed and indeed varied systematically within the resulting light field, spatially and directionally. Inter-reflections predominantly affect the light density spectrum and have less impact on the light vector spectrum. It is important to consider these differential effects for their consequences on the colour rendering of 3-dimensional objects and people.

Flavobacteria, which can be found in marine environments, are able to grow in highly organized colonies producing vivid iridescent colorations. While much is known about the biology of these organisms, their design potential as responsive media in user interfaces has not been explored. Our paper aims at bridging this gap by providing insights into the type, degree, and duration of change in Flavobacteria's expression, i.e., their living aesthetics. We present a tool to capture and characterize these changes concerning form, texture and iridescent color. To support the long-term study of their living aesthetics, we designed Flavorium. This bio-digital artifact provides the necessary habitat conditions for Flavobacteria to thrive for a month. Granting insights into the responsive behavior of this organism, this work presents a design space, vocabulary, and application concepts to inspire HCI and design scholars to investigate the complex temporal qualities of living media for future user interfaces.

Product lighting design is a laborious and time-consuming task. With product illustrations being increasingly rendered, the lighting challenge transferred to the virtual realm. Our approach targets lighting design in the context of a scene with fixed objects, materials, and camera parameters, illuminated by environmental lighting. Our solution offers control over the depiction of material characteristics and shape details by optimizing the illuminating environment-map. To that end, we introduce a metric that assesses the shape and material cues in terms of the designed appearance. We formalize the process and support steering the outcome using additional design constraints. We illustrate our solution with several challenging examples.