Lighting patterns and the flow of light

Cuttle, Christopher

doi:10.1177/096032717100300301

Cited by 69 publications

(54 citation statements)

References 3 publications

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“…Our method allows us to find special points in the light field, for instance, where the light vector vanishes and the structure of the local light field is dominated by a squash tensor. This is a formal scientific approach to express the quality of light in the scene numerically, whereas the "flow of light" [4,24], which is based on object appearance, provides only a qualitative description. Besides, the second-order spherical harmonics description can be used as lighting input for rendering systems.…”

Section: Discussionmentioning

confidence: 99%

Representing the light field in finite three-dimensional spaces from sparse discrete samples

2009

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We present a method for measurement and reconstruction of light fields in finite spaces. Using a custommade device called a plenopter, we can measure spatially and directionally varying radiance distribution functions from a real-world scene up to their second-order spherical harmonics approximations. Interpolating between measurement points, we can recover this function for arbitrary points of a scene. We visualized the global structure of the light field using light tubes, which gives an intuitive description of the flux propagation throughout three-dimensional scenes and provides information about the quality of light in the scenes. Our second-order reconstructions are sufficient to render convex matte objects and therefore have a direct interest for computer graphics applications.

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Section: Discussionmentioning

confidence: 99%

Representing the light field in finite three-dimensional spaces from sparse discrete samples

2009

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“…The quality of the light field, i.e., the directional properties of the illumination, strongly affects the appearance of an object positioned at that point [1][2][3][4][5][6]. For instance, in fully diffuse illumination even a specular metallic object looks rather matte.…”

Section: Introductionmentioning

confidence: 99%

“…Because surface elements of a convex object are illuminated from half spaces, the surface irradiance is typically fairly smooth, even if the angular distribution of the radiance is spiky [1,2]. If the primary and secondary light sources are relatively distant from the region of interest, the spatial variations of the angular distribution will be minor over that region.…”

Section: Introductionmentioning

confidence: 99%

Structure of light fields in natural scenes

2009

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] of natural scenes are highly complex and vary within a scene from point to point. However, in many applications complex lighting can be successfully replaced by its low-order approximation [J. Opt. Soc. Am. A 18, 2448 Appl. Opt. 46, 7308 (2007)]. The purpose of this research is to investigate the structure of light fields in natural scenes. We describe the structure of light fields in terms of spherical harmonics and analyze their spatial variation and qualitative properties over scenes. We consider several types of natural scene geometries. Empirically and via modeling, we study the typical behavior of the first-and second-order approximation of the local light field in those scenes. The first-order term is generally known as the "light vector" and has an immediate physical meaning. The quadrupole component, which we named "squash tensor," is a useful addition as we show in this paper. The measurements were done with a custom-made device of novel design, called a "Plenopter," which was constructed to measure the light field in terms of spherical harmonics up to the second order. In different scenes of similar geometries, we found structurally similar light fields, which suggests that in some way the light field can be thought of as a property of the geometry. Furthermore, the smooth variation of the light field's low-order components suggests that, instead of specifying the complete light field of the scene, it is often sufficient to measure the light field only in a few points and rely on interpolation to recover the light field at arbitrary points of the scene.

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“…2. Vector/Scalar Illumination Ratio (V/S) [5,6,7] produced from the two location points facing forward from each of the 6 lighting scenarios. V/S is an index for appearance and dimensionality within a space.…”

Section: Lighting Evaluation Criteriamentioning

confidence: 99%

Evaluations of Low ambient task - surround lighting system in a simulated environment

Ngai

2016

J Sol State Light

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Task -Ambient lighting provides energy saving but space surrounding the users can be dim and unpleasant. This study proposed a solution of an additional Surround Layer of light. Though a series of simulated lighting scenarios, it examined illumination requirements, dimensionality and appearance of the space by the use of Vector/Scalar and Task/Vertical Illumination Ratios. They were evaluated under several illuminance requirements, Task-Surround combinations and Surround Light source sizes. The results showed that by adding a Surround Light Layer, visual appearance of space surrounding the users could be enhanced and energy savings could be achieved.

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Lighting patterns and the flow of light

Cited by 69 publications

References 3 publications

Representing the light field in finite three-dimensional spaces from sparse discrete samples

Representing the light field in finite three-dimensional spaces from sparse discrete samples

Structure of light fields in natural scenes

Evaluations of Low ambient task - surround lighting system in a simulated environment

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