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The light density, direction and diffuseness are important indicators of the spatial and form-giving character of light. Mury presented a method to describe, measure and visualise the light field’s structure in terms of light density and direction variations in three-dimensional spaces. We extend this work with a theoretical and empirical review of four diffuseness metrics leading to a novel metric proposal DXia. In particular, the relationships between these diffuseness metrics were studied using a model named ‘probe in a sphere’. Diffuseness metric DXia re-frames the diffuseness metric of Cuttle in an integral description of the light field. It fulfils all diffuseness criteria and has the advantage that it can be used in a global, integrated description of the light flow and diffuseness throughout three-dimensional spaces. [ABSTRACT FROM AUTHOR]

We introduce a way to simultaneously measure the light density, light vector and diffuseness of the light field using a cubic illumination meter based on the spherical harmonics representation of the light field. This approach was applied to six light probe images of natural scenes and four real scenes built in our laboratory, and the results were compared to those obtained using Cuttle’s method. We also demonstrated a way to simultaneously and intuitively visualise the global structure of the light distribution using light tubes and colour coding for the light density, light flow and diffuseness variations through the space. Together with Mury’s work, we have a complete way to describe, measure and visualise the local and global low-order properties of light distributions in three-dimensional spaces. [ABSTRACT FROM AUTHOR]

This paper investigates the interaction between retail lighting and textiles to provide retailers and lighting designers with a set of physical textile objects that can be used to test the visual effect of a lighting setting. Since the relationships between optical aspects of lighting-textiles interactions and subjective qualities associated with them have not been systematically investigated, we conducted two experiments to study those relationships. The first experiment concerned photometric measurements of textiles in order to categorize the reflectance types. The second experiment examined human observers' judgments of a range of material-expressing qualities, such as shininess and softness, in two canonical types of lighting. The textiles for which the differences in those qualities were maximal were used in designing a lighting probe set. [ABSTRACT FROM AUTHOR]

At the start of the 20th century, Moritz von Rohr invented the synopter: a device that removes 3D depth cues that arise from binocular disparities and vergence. In the absence of these visual cues, the observer is less aware of the physical flatness of the picture. This results in a surprisingly increased depth impression of pictorial space, historically known as the 'plastic effect'. In this paper we present a practical design to produce a synopter and explore which elements of a painting influence the plastic effect. In the first experiment we showed 22 different paintings to a total of 35 observers, and found that they rate the synoptic effect rather consistent over the various paintings. Subsequent analyses indicated that at least three pictorial cues were relevant for the synoptic effect: figure-ground contrast, compositional depth and shadows. In experiment 2, we used manipulated pictures where we tried to strengthen or weaken these cues. In all three cases we found at least one effect that confirmed our hypothesis. We also found substantial individual differences: some observers experience little effect, while others are very surprised by the effect. A stereo acuity test revealed that these differences could not be attributed to how well disparities are detected. Lastly, we informally tested our newly designed synopter in museums and found similar idiosyncratic appraisal. But the device also turned out to facilitate discussions among visitors. [ABSTRACT FROM AUTHOR]

At the start of the 20th century, Moritz von Rohr invented the synopter: a device that removes 3D depth cues that arise from binocular disparities and vergence. In the absence of these visual cues, the observer is less aware of the physical flatness of the picture. This results in a surprisingly increased depth impression of pictorial space, historically known as the 'plastic effect'. In this paper we present a practical design to produce a synopter and explore which elements of a painting influence the plastic effect. In the first experiment we showed 22 different paintings to a total of 35 observers, and found that they rate the synoptic effect rather consistent over the various paintings. Subsequent analyses indicated that at least three pictorial cues were relevant for the synoptic effect: figure-ground contrast, compositional depth and shadows. In experiment 2, we used manipulated pictures where we tried to strengthen or weaken these cues. In all three cases we found at least one effect that confirmed our hypothesis. We also found substantial individual differences: some observers experience little effect, while others are very surprised by the effect. A stereo acuity test revealed that these differences could not be attributed to how well disparities are detected. Lastly, we informally tested our newly designed synopter in museums and found similar idiosyncratic appraisal. But the device also turned out to facilitate discussions among visitors. [ABSTRACT FROM AUTHOR]