An analytical model for the celestial distribution of polarized light, accounting for polarization singularities, wavelength and atmospheric turbidity

Wang, Xin; Gao, Jun; Fan, Zhiguo; Roberts, Nicholas W.

doi:10.1088/2040-8978/18/6/065601

Cited by 25 publications

(27 citation statements)

References 58 publications

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“…As a result, degree of polarization can be considered a measure of signal strength for an animal using the skylight pattern of angles of polarization as an orientation cue. Relative to the sun or moon’s position, this angle-of-polarization pattern is similar across a range of conditions (Gál, et al ., 2001; Hegedüs et al ., 2007; Barta et al ., 2014; Wang et al ., 2016). In contrast, the degree of polarization decreases as a result of cloud cover and atmospheric turbidity (Labhart, 1999; Hegedüs et al ., 2007; Wang et al ., 2016) as well as being affected by light pollution on moonlit nights in urban areas (Kyba et al ., 2011).…”

Section: Introductionmentioning

confidence: 99%

“…Relative to the sun or moon’s position, this angle-of-polarization pattern is similar across a range of conditions (Gál, et al ., 2001; Hegedüs et al ., 2007; Barta et al ., 2014; Wang et al ., 2016). In contrast, the degree of polarization decreases as a result of cloud cover and atmospheric turbidity (Labhart, 1999; Hegedüs et al ., 2007; Wang et al ., 2016) as well as being affected by light pollution on moonlit nights in urban areas (Kyba et al ., 2011). Since lunar skylight is far dimmer than solar skylight, contributions to celestial light from other sources can reduce the maximum observable degree of polarization in the night sky, when these light sources have either a low degree of polarization ( e.g.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Orienting to Polarized Light at Night—Matching Lunar Skylight to Performance in a Nocturnal Beetle

Foster

Kirwan

Jundi

et al. 2018

Preprint

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A degree-of-polarization threshold for orientation behaviour is 15 reported for nocturnal dung beetle Escarabaeus satyrus in the context 16 of measurements showing changes in the degree of polarization of 17 skylight with lunar phase. 18 Abstract 19For polarized light to inform behaviour, the typical range of degrees of 20 polarization observable in the animal's natural environment must be 21 above the threshold for detection and interpretation. Here we present 22 the first investigation of the degree of linear polarization threshold for 23 orientation behaviour in a nocturnal species, with specific reference to 24 the range of degrees of polarization measured in the night sky. An 25 effect of lunar phase on the degree of polarization of skylight was 26 found, with smaller illuminated fractions of the moon's surface 27 corresponding to lower degrees of polarization in the night sky. We 28 found that South African dung beetle Escarabaeus satyrus 29 (Boheman, 1860) can orient to polarized light for a range of 30 degrees of polarization similar to that observed in diurnal insects, 31 reaching a lower threshold between 0.04 and 0.32, possibly as low as 32 2 0.11. For degrees of polarization lower than 0.23, as measured on a 33 crescent moon night, orientation performance was considerably 34 weaker than that observed for completely linearly-polarized stimuli, 35 but was nonetheless stronger than in the absence of polarized light. 36

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Orienting to Polarized Light at Night—Matching Lunar Skylight to Performance in a Nocturnal Beetle

Foster

Kirwan

Jundi

et al. 2018

Preprint

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“…I ∞ c (T, φ, θ) is computed according to Eqs. (12) and (13). The target with aerial perspective effectÎ VO is calculated using Eq.…”

Section: Proposed Glsl Fragment Shadermentioning

confidence: 96%

“…Such scattering models can be analyzed from captured skies using sky illumination models [1][2][3][4][5][6][7]. Due to its simplicity and accuracy for scattering modeling, a heuristic parameter called turbidity (T) has been used to categorize atmospheric conditions [8][9][10][11][12]. Following that approach, we propose a full-spectrum turbidity-based aerial perspective model that enables us to render realistic aerial perspective effects in real time.…”

Section: Introductionmentioning

confidence: 99%

Real-time rendering of aerial perspective effect based on turbidity estimation

Morales

Oishi

Ikeuchi

2017

IPSJ T Comput Vis Appl

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In real outdoor scenes, objects distant from the observer suffer from a natural effect called aerial perspective that fades the colors of the objects and blends them to the environmental light color. The aerial perspective can be modeled using a physics-based approach; however, handling with the changing and unpredictable environmental illumination as well as the weather conditions of real scenes is challenging in terms of visual coherence and computational cost. In those cases, even state-of-the-art models fail to generate realistic synthesized aerial perspective effects. To overcome this limitation, we propose a real-time, turbidity-based, full-spectrum aerial perspective rendering approach. First, we estimate the atmospheric turbidity by matching luminance distributions of a captured sky image to sky models. The obtained turbidity is then employed for aerial perspective rendering using an improved scattering model. We performed a set of experiments to evaluate the scattering model and the aerial perspective model. We also provide a framework for real-time aerial perspective rendering. The results confirm that the proposed approach synthesizes realistic aerial perspective effects with low computational cost, outperforming state-of-the-art aerial perspective rendering methods for real scenes.

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“…Light in the sky that scatters in the atmosphere has a maximum of around 60% (Wang et al, 2016) and can be around 40% in the ocean (Cronin et al, 2003a). Polarized animal signals can have a percentage polarizations of up to 80% (Marshall et al, 2014b.…”

Section: Introductionmentioning

confidence: 99%

Circular polarization vision in stomatopod crustaceans

Templin¹

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Perhaps due to relative speed and reliability, the information that light provides is useful to many animals. As a result, visual systems are a major, sensory system in several animal groups. Various aspects of vision become tuned by the environment and behavioural need, including relative sensitivity, speed, colour, and in some species, polarization. The stomatopod crustaceans (mantis shrimps) are remarkable in that they possess, at the retinal level, the most complex colour system known including 12 spectral sensitivities. However, like other crustaceans their lifestyles may also rely on the information they can receive from polarization. This is evident from the range of polarization sensitive areas of their subdivided eye. The hemispheric regions of the stomatopod eye are linear polarization sensitive, in a total of four different e-vector orientations. Additionally, stomatopods are able to rotate their eyes making the actual angle of polarization sensitivity to the outside world arbitrary.Perhaps most interesting in the context of polarization vision is the function of the eighth retinular cells, known as R8, of rows 5 and 6 of the midband region. These birefringent cells act as quarter-wave retarders allowing stomatopods to be sensitive to circularly polarized light (CPL). This ability has yet to be demonstrated in other animals and compared to linear polarization vision (LPV), circular polarization vision (CPV) is not well understood.The aim of this thesis was to further investigate rows 5 and 6 of the midband in a range of stomatopod species, using both behavioural and anatomical techniques. Firstly, through modelling the birefringent properties of the R8 in six species, it is revealed that the ability to discriminate CPL is shared among many stomatopods (Chapter 2). Adaptive pressure to maintain the size of the R8 cell, achieving quarter-wave retardance, suggests that it provides an important role for stomatopods. However, one species included in this study, Haptosquilla trispinosa, is likely sensitive to a different ellipticity of polarized light than circular.Since its discovery in 2008, it was hypothesized that circular polarization vision could provide a covert communication system for stomatopods. Chapter 3 uses behavioural paradigms to examine the discrimination abilities of Gonodactylaceus falcatus, a species of stomatopod with extensive polarization patterns on their bodies, and demonstrates that they use circular polarization as a signal for burrow occupancy. However, as variation in body patterns exist between species, with some species having none at all, other roles for CPL need to be The research presented in this thesis provides evidence contrary to the assumption that row 5 and 6 of the midband provide all species with CPV, despite appearing anatomically identical. We present a number of alternative hypotheses for the function of these rows, highlighting the likelihood that for different species specific roles exist.iv

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An analytical model for the celestial distribution of polarized light, accounting for polarization singularities, wavelength and atmospheric turbidity

Cited by 25 publications

References 58 publications

Orienting to Polarized Light at Night—Matching Lunar Skylight to Performance in a Nocturnal Beetle

Orienting to Polarized Light at Night—Matching Lunar Skylight to Performance in a Nocturnal Beetle

Real-time rendering of aerial perspective effect based on turbidity estimation

Circular polarization vision in stomatopod crustaceans

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