Contrast measures for predicting perceptual effects of daylight in architectural renderings

Abstract

Daylit architecture is perceived as a dynamic luminous composition, yet most existing performance metrics were designed to evaluate natural illumination for its ability to adequately illuminate a twodimensional task surface and avoid glare-based discomfort. It may be argued that task-driven approaches based on surface illumination and glare ignore the likelihood that contrast can provide positive impacts on our visual perception of space. Advances in these metrics to accommodate climate-based sky conditions and occupant behavior have improved our ability to evaluate task illumination and glare, yet the same attention has not been paid to evaluating positive perceptual responses to daylight. Existing studies have attempted to link subjective ratings of composition to simple global contrast metrics without reaching consensus. More advanced metrics have been developed in computational graphics and vision fields, but have not been applied to studies in qualitative lighting research. This paper introduces the results from an online experiment where subject ratings of daylight composition are compared to quantitative contrast measures across a series of renderings. This paper will identify which measures correlate to subjects' ratings of visual interest, and introduces a modified contrast algorithm, which can be used as a novel prediction model for visual interest in daylit renderings.

Application of High-Dynamic Range Imaging Techniques in Architecture: A Step toward High-Quality Daylit Interiors?

“…For accelerating the development of appearance-driven performance indicators such those developed in [16], some methodological challenges should be addressed. Indeed, the classical method for exploring the appearance of lit spaces is the psychophysical approach: the relationship between physical measurements of (visual) stimuli and sensations/perceptions that those stimuli evoke to observers is studied.…”

Daylight Within a Room in the Eyes of Architecture Students

“…The visual comfort, daylight luminous comfort (Xue et al, 2016), daylight satisfaction (Galasiu and Veitch, 2006;Galatioto and Beccali, 2016), as well as a well day-lit space attributes and indices are still ambiguous concepts which relate to various luminous conditions depending on viewer's subjective perception, preferences and knowledge. Due to the constant changes in temporal, spatial and spectral characteristics of daylight, scientific comprehension of visual and non-visual comfort relates to the illumination levels, (Bodmann, 1992;Nabil and Mardaljevic, 2006), luminance patterns, (Loe et al, 2000;Van Den Wymelenberg et al, 2009), uniformity or contrast (Rockcastle et al, 2017), satisfaction with visual environment (Veitch, 2001;Galasiu and Veitch, 2006), the anti-glare measures (Wienold and Christoffersen, 2006;Wienold and Bodart, 2018), a control of daylight provision including various shading system control (Wong and Istiadji, 2004;Konis, 2013), the bio-responses correlated with ipRGCs (Lucas et al, 2014), an access to view and view ratings (Boyce et al, 2003;Tuaycharoen and Tregenza, 2007;Veitch and Galasiu, 2012), the aesthetics and a visual perception of light spaciousness (Johansson et al, 2010). The researchers propose different qualitative and descriptive methods illustrating the human perception of daylit space characteristics.…”

A human-centric approach to assess daylight in buildings for non-visual health potential, visual interest and gaze behavior

“…To predict occupant impressions of visual interest, the authors developed a quantitative model based on subjective ratings of visual interest in daylight renderings gathered through an online survey [16]. The survey used in this experiment asked participants to rank a selection of renderings: nine architectural spaces under three sunny sky conditions (modeled in Rhino, rendered using Radiance, and tone mapped using pcond to a standard Low Dynamic Range (LDR) computer display).…”

“…This modified algorithm, referred to as modified Spatial Contrast mSC, is defined in Appendix 1.2. The cumulative predictive probabilities for each rating on the scale 1-7, from calming to exciting, best fit the equation The full results of the online experiment and the analysis used to generate the predictive model presented here have been published in more depth by the authors in [16], [46], but the integration of these thresholds into an immersive analysis allows us to see, for the first time ever, the effect of view direction on predictions of visual interest in an architectural space. Whereas the authors previous work focused on predicting impressions using a 2D rectangular rendering with a fixed view direction, this paper allows for the immersive assessment across an entire 360° view range, revealing the effects of orientation and architectural composition on impressions of excitement and calm.…”

“…As described in Section 3.1.2, the mSC model presented in this paper was derived from an experiment, which compared subjective ratings of 2D tone-mapped renderings to a range of contrast algorithms [16] and found that one modified algorithm could be used to predict ratings of calming -exciting.…”