An optimal elliptical retarder for rotating compensator imaging polarimetry

2021 ◽  
Author(s):  
Dale Gottlieb ◽  
Oriol Arteaga
Keyword(s):  
Imaging Polarimetry

[ITAL]HUBBLE SPACE TELESCOPE[/ITAL][ITAL]Hubble Space Telescope[/ITAL] Imaging Polarimetry of η Carinae

1999 ◽  
Vol 118 (3) ◽  
pp. 1320-1337 ◽  
Author(s):  
R. E. Schulte-Ladbeck ◽  
A. Pasquali ◽  
M. Clampin ◽  
A. Nota ◽  
D. J. Hillier ◽  
...  
Keyword(s):  
Hubble Space Telescope ◽  
Space Telescope ◽  
Imaging Polarimetry

Ultraviolet Imaging Polarimetry of Narrow‐Line Radio Galaxies

1999 ◽  
Vol 514 (2) ◽  
pp. 579-586 ◽  
Author(s):  
Todd Hurt ◽  
Robert Antonucci ◽  
Ross Cohen ◽  
Anne Kinney ◽  
Julian Krolik
Keyword(s):  
Radio Galaxies ◽  
Narrow Line ◽  
Imaging Polarimetry

scholarly journals Paperboard Coating Detection Based on Full-Stokes Imaging Polarimetry

Sensors ◽  
2020 ◽  
Vol 21 (1) ◽  
pp. 208
Author(s):  
Javier Brugés Martelo ◽  
Jan Lundgren ◽  
Mattias Andersson
Keyword(s):  
Food Packaging ◽  
Imaging Systems ◽  
Gaussian Kernel ◽  
Support Vector ◽  
Camera System ◽  
Distance Correlation ◽  
Imaging Polarimetry ◽  
Packaging Industry ◽  
Thickness Variations

The manufacturing of high-quality extruded low-density polyethylene (PE) paperboard intended for the food packaging industry relies on manual, intrusive, and destructive off-line inspection by the process operators to assess the overall quality and functionality of the product. Defects such as cracks, pinholes, and local thickness variations in the coating can occur at any location in the reel, affecting the sealable property of the product. To detect these defects locally, imaging systems must discriminate between the substrate and the coating. We propose an active full-Stokes imaging polarimetry for the classification of the PE-coated paperboard and its substrate (before applying the PE coating) from industrially manufactured samples. The optical system is based on vertically polarized illumination and a novel full-Stokes imaging polarimetry camera system. From the various parameters obtained by polarimetry measurements, we propose implementing feature selection based on the distance correlation statistical method and, subsequently, the implementation of a support vector machine algorithm that uses a nonlinear Gaussian kernel function. Our implementation achieves 99.74% classification accuracy. An imaging polarimetry system with high spatial resolution and pixel-wise metrological characteristics to provide polarization information, capable of material classification, can be used for in-process control of manufacturing coated paperboard.

First Near-infrared Imaging Polarimetry of Young Stellar Objects in the Circinus Molecular Cloud

2018 ◽  
Vol 234 (2) ◽  
pp. 42 ◽  
Author(s):  
Jungmi Kwon ◽  
Takao Nakagawa ◽  
Motohide Tamura ◽  
James H. Hough ◽  
Minho Choi ◽  
...  
Keyword(s):  
Molecular Cloud ◽  
Near Infrared ◽  
Infrared Imaging ◽  
Young Stellar Objects ◽  
Near Infrared Imaging ◽  
Stellar Objects ◽  
Imaging Polarimetry

scholarly journals ERROR ANALYSIS OF THE DISPERSION-COMPENSATED WIDE-BAND POLARIZATION SAGNAC INTERFEROMETER

2020 ◽  
Vol XLIII-B1-2020 ◽  
pp. 621-625
Author(s):  
J. Zhu ◽  
K. Zong ◽  
F. Goudail ◽  
N. Zhang ◽  
X. Hou
Keyword(s):  
Diffraction Efficiency ◽  
Incident Light ◽  
Wide Band ◽  
Reconstruction Error ◽  
Optical Elements ◽  
Blazed Grating ◽  
Interference Fringes ◽  
Splitting Ratio ◽  
Imaging Polarimetry ◽  
Modulation Degree

Abstract. Imaging polarimetry can obtain two-dimensional intensity distribution information and its corresponding states of polarization from the target simultaneously. Sagnac polarization imaging interferometer is one of the typical channeled polarimetry technologies. By splitting the incident light through the triangular optical structure, the polarization information of the target is modulated into the interference fringes and can be obtained by the demodulation algorithm. The non-ideal optical elements in the system will cause reconstruction errors. This article analyses several factors that affect the measurement accuracy, including the splitting ratio of polarization beam splitter and the diffraction efficiency of the blazed grating. We derive the modified intensity formula and obtain interference patterns through numerical simulations. By calculating the modulation degree of interference fringes and reconstruction error under different non-ideal parameters, we have come to the conclusion that to meet the requirement of modulation degree > 0.5 and reconstruction error < 10%, the beam splitting ratio of the PBS should be α < 1.22. The diffraction efficiency ratio of s-polarization to p-polarization of the blazed grating should be ηs/ηp > 0.83, and the first-order diffraction efficiency should be η1 > 79%.

scholarly journals How the clear-sky angle of polarization pattern continues underneath clouds: full-sky measurements and implications for animal orientation

2001 ◽  
Vol 204 (17) ◽  
pp. 2933-2942 ◽  
Author(s):  
István Pomozi ◽  
Gábor Horváth ◽  
Rüdiger Wehner
Keyword(s):  
Single Scattering ◽  
Degree Of Polarization ◽  
Polarization Pattern ◽  
Clear Sky ◽  
Animal Navigation ◽  
Imaging Polarimetry ◽  
Polarization Compass ◽  
Sky Conditions ◽  
Perceptual Threshold ◽  
Animal Orientation

SUMMARY One of the biologically most important parameters of the cloudy sky is the proportion P of the celestial polarization pattern available for use in animal navigation. We evaluated this parameter by measuring the polarization patterns of clear and cloudy skies using 180° (full-sky) imaging polarimetry in the red (650nm), green (550nm) and blue (450nm) ranges of the spectrum under clear and partly cloudy conditions. The resulting data were compared with the corresponding celestial polarization patterns calculated using the single-scattering Rayleigh model. We show convincingly that the pattern of the angle of polarization (e-vectors) in a clear sky continues underneath clouds if regions of the clouds and parts of the airspace between the clouds and the earth surface (being shady at the position of the observer) are directly lit by the sun. The scattering and polarization of direct sunlight on the cloud particles and in the air columns underneath the clouds result in the same e-vector pattern as that present in clear sky. This phenomenon can be exploited for animal navigation if the degree of polarization is higher than the perceptual threshold of the visual system, because the angle rather than the degree of polarization is the most important optical cue used in the polarization compass. Hence, the clouds reduce the extent of sky polarization pattern that is useful for animal orientation much less than has hitherto been assumed. We further demonstrate quantitatively that the shorter the wavelength, the greater the proportion of celestial polarization that can be used by animals under cloudy-sky conditions. As has already been suggested by others, this phenomenon may solve the ultraviolet paradox of polarization vision in insects such as hymenopterans and dipterans. The present study extends previous findings by using the technique of 180° imaging polarimetry to measure and analyse celestial polarization patterns.

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