Polarized Light Angle Reflectance Instrument I Polarized Incidence (POLAR:I)

Sarto, Anthony W.; Woldemar, Christopher M.; Vanderbilt, V. C.

doi:10.1117/12.962893

Cited by 6 publications

(4 citation statements)

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“…All our findings are in accord with the earlier results of Shul 'gin and Moldau (1964), Vanderbilt and Grant (1985a, b), Vanderbilt et al (1985a, b), Grant (1987), Grant et al (1987aGrant et al ( , b, 1993 and Sarto et al (1989), who measured the polarized, non-polarized and specular reflectance of leaves of many different plant species as functions of the leaf surface features in the visible and near-infrared parts of the spectrum by pointsource polarimetry. They found that in some viewing directions the surface reflection is so large that leaves appear white instead of green.…”

Section: Reflection-polarization Characteristics Of Plant Surfacessupporting

confidence: 93%

Does reflection polarization by plants influence colour perception in insects? Polarimetric measurements applied to a polarization-sensitive model retina ofPapiliobutterflies

Horváth

Gál

Labhart

et al. 2002

Journal of Experimental Biology

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SUMMARYUsing imaging polarimetry, we have measured some typical reflection-polarization patterns of plant surfaces (leaves and flowers) under different illuminations. Using a quantitative model to determine photon absorptions in the weakly polarization-sensitive (PS≈2)photoreceptors of Papilio butterflies, we have calculated the influence of reflection polarization on the colours of leaves and flowers perceived by Papilio. Compared with a retina containing polarization-blind colour receptors, the colour loci of specularly reflecting and, thus, strongly polarizing areas on a plant are slightly shifted, which could cause the perception of false colours. However, the colour of specularly reflecting surfaces is strongly masked by white glare, which may prevent the perception of polarization-induced hue shifts. Although the perception of polarizational false colours by Papilio butterflies was previously demonstrated with artificial, strongly colour-saturated and totally linearly polarized stimuli, we expect that the weak polarization sensitivity of Papilio photoreceptors hardly influences colour perception under natural conditions.

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Section: Reflection-polarization Characteristics Of Plant Surfacessupporting

confidence: 93%

Does reflection polarization by plants influence colour perception in insects? Polarimetric measurements applied to a polarization-sensitive model retina ofPapiliobutterflies

Horváth

Gál

Labhart

et al. 2002

Journal of Experimental Biology

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“…Sometimes however, it is just the opposite: the detectors are fixed and the light source is mounted on a rotation stage (Okayama, 1996). Finally, in other devices, all components are fixed (Sarto et al, 1989). In all reports, measurements are performed in the visible/near-infrared region, in one to several wavebands, and in polarized or non-polarized conditions, but very few of them combined both the spectral and directional dimensions.…”

Section: Introductionmentioning

confidence: 99%

A new spectrogoniophotometer to measure leaf spectral and directional optical properties

Combes

Bousquet

Jacquemoud

et al. 2007

Remote Sensing of Environment

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“…The measurement of leaf directional properties is complex and needs sophisticated devices such as a gonio-reflectometer (e.g. Combes et al, 2007;Woolley, 1971), an imaging sphere (Sarto, Woldemar, & Vanderbilt, 1990), or a conoscope (Comar et al, 2012). Other existing systems could be used (Marschner, Westin, Lafortune, & Torrance, 2000), but no results have been reported in the literature for leaves.…”

Section: Introductionmentioning

confidence: 99%

ACT: A leaf BRDF model taking into account the azimuthal anisotropy of monocotyledonous leaf surface

Comar

Baret

Obein

et al. 2014

Remote Sensing of Environment

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International audienceKeywords: Sorghum Wheat Leaf Surface roughness BRDF BRF Reflectance Conoscope Azimuthal anisotropy Optical properties Goniometer Physical model Refractive index Leaf reflectance of monocotyledons generally displays a strong azimuthal anisotropy due to the longitudinal orientation of the veins. The Cook and Torrance (CT) bidirectional reflectance distribution function model was adapted to account for this distinctive feature. The resulting ACT (Anisotropic Cook and Torrance) model is based on the decomposition of the roughness parameter into two perpendicular components. It is evaluated on sorghum (Sorghum halepense) and wheat (Triticum durum) leaf BRF (Bidirectional Reflectance Factor) measurements acquired using a conoscope system. Results show that the ACT model fits the measurements better than azimuthally isotropic surface models: the root mean square error computed over all the BRF measurements for both leaves decreases from ≈0.06 for the Lambertian model to ≈0.04 for the CT model and down to ≈0.03 for the ACT model. The adjusted value of the refraction index is plausible (n ≈ 1.32) for both leaves while the retrieved roughness values perpendicular to the veins (sorghum = 0.56; wheat = 0.46) is about two times larger than that parallel to the veins (sorghum = 0.27; wheat = 0.18). Nonetheless, the observed residual discrepancies between the ACT model simulations and the measurements may be explained mainly by the Lambertian assumption of the volume scattering

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Polarized Light Angle Reflectance Instrument I Polarized Incidence (POLAR:I)

Cited by 6 publications

References 0 publications

Does reflection polarization by plants influence colour perception in insects? Polarimetric measurements applied to a polarization-sensitive model retina ofPapiliobutterflies

Does reflection polarization by plants influence colour perception in insects? Polarimetric measurements applied to a polarization-sensitive model retina ofPapiliobutterflies

A new spectrogoniophotometer to measure leaf spectral and directional optical properties

ACT: A leaf BRDF model taking into account the azimuthal anisotropy of monocotyledonous leaf surface

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