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A new astronomical photo-polarimeter that can measure linear polarization of point sources simultaneously in three spectral bands was designed and built in Indian Institute of Astrophysics. The polarimeter has a Calcite beam-displacement…

Instrumentation and Methods for Astrophysics · Physics 2015-06-30 A. V. Raveendran , G. Srinivasulu , S. Muneer , M. V. Mekkaden , N. Jayavel , M. R. Somashekar , K. Sagayanathan , S. Ramamoorthy , M. J. Rosario , K. Jayakumar

The ability of NICMOS to perform high accuracy polarimetry is currently hampered by an uncalibrated residual instrumental polarization at a level of 1.2-1.5%. To better quantify and characterize this residual we obtained observations of…

Polarimetric interferometry is a method allowing the study of the distribution of polarized flux at diffraction-limited resolution. Its basic observable is the ratio $\mathcal{R}$ of the visibilities of the object in two orthogonal…

Instrumentation and Methods for Astrophysics · Physics 2019-02-27 Boris Safonov , Pavel Lysenko , Maria Goliguzova , Dmitry Cheryasov

Polarization is one of the fundamental natures of electromagnetic radiation. The detection of polarization or polarized photons from distant X-ray radiating systems (such as X-ray binaries (XBs), active galactic nuclei (AGN), pulsars, and…

High Energy Astrophysical Phenomena · Physics 2026-01-01 Arbind Pradhan , Sree Bhattacherjee , Biplob Sarkar

Polarization information of the light can provide rich cues for computer vision and scene understanding tasks, such as the type of material, pose, and shape of the objects. With the advent of new and cheap polarimetric sensors, this imaging…

Computer Vision and Pattern Recognition · Computer Science 2024-01-03 Joaquin Rodriguez , Lew-Fock-Chong Lew-Yan-Voon , Renato Martins , Olivier Morel

The study of magnetars is of particular relevance since these objects are the only laboratories where the physics in ultra-strong magnetic fields can be directly tested. Until now, spectroscopic and timing measurements at X-ray energies in…

High Energy Astrophysical Phenomena · Physics 2015-06-18 Roberto Taverna , Fabio Muleri , Roberto Turolla , Paolo Soffitta , Sergio Fabiani , Luciano Nobili

The effects of strong gravity on the polarization of the Compton reflection from an X-ray illuminated accretion disc are studied. The gravitational field of a rotating black hole influences Stokes parameters of the radiation along the…

Astrophysics · Physics 2007-05-23 M. Dovciak , V. Karas , G. Matt

We demonstrate experimentally ghost optical coherence tomography using a broadband incoherent supercontinuum light source with shot-to-shot random spectral fluctuations. The technique is based on ghost imaging in the spectral domain where…

We present two backscattering polarimetric scanning setups based on point-illumination schemes, that are designed to probe the optical properties of subsurface media. We describe their advantages and limitations, characterize their…

Advances in vectorial polarisation-resolved imaging are bringing new capabilities to applications ranging from fundamental physics through to clinical diagnosis. Imaging polarimetry requires determination of the Mueller matrix (MM) at every…

Photons preferentially Compton scatter perpendicular to the plane of polarisation. This property can be exploited to design instruments to measure the linear polarisation of hard X-rays ($\sim$10 - 100 keV). Photons may undergo two…

Instrumentation and Detectors · Physics 2023-01-25 Ettore Del Monte , Sergio Fabiani , Mark Pearce

The development of micropixel gas detectors, capable to image tracks produced in a gas by photoelectrons, makes possible to perform polarimetry of X-ray celestial sources in the focus of grazing incidence X-ray telescopes. HXMT is a mission…

We have built and tested a compact, low-cost, but very-high-performance astronomical polarimeter based on a continuously rotating half-wave plate and a high-speed imaging detector. The polarimeter is suitable for small telescopes up to ~1 m…

Instrumentation and Methods for Astrophysics · Physics 2023-02-08 Jeremy Bailey , Daniel V. Cotton , Ain De Horta , Lucyna Kedziora-Chudczer , Om Shastri

Since specular reflection often exists in the real captured images and causes deviation between the recorded color and intrinsic color, specular reflection separation can bring advantages to multiple applications that require consistent…

Computer Vision and Pattern Recognition · Computer Science 2022-01-26 Sijia Wen , Yingqiang Zheng , Feng Lu

The polarization state of starlight reflected by a planetary atmosphere uniquely reveals coverage, particle size, and composition of aerosols as well as changing cloud patterns. It is not possible to obtain a comparable level of detailed…

The investigation of polarized light of protoplanetary disks is key for constraining the dust properties, disk morphology and embedded magnetic fields. However, different polarization mechanisms and the diversity of dust grain shapes and…

Solar and Stellar Astrophysics · Physics 2019-07-17 Robert Brunngräber , Sebastian Wolf

6D pose estimation pipelines that rely on RGB-only or RGB-D data show limitations for photometrically challenging objects with e.g. textureless surfaces, reflections or transparency. A supervised learning-based method utilising…

Computer Vision and Pattern Recognition · Computer Science 2023-08-22 Patrick Ruhkamp , Daoyi Gao , HyunJun Jung , Nassir Navab , Benjamin Busam

Polarizations of electromagnetic waves from distant galaxies are known to be correlated with the source orientations. These quantities have been used to search for signals of cosmological birefringence. We review and classify transformation…

Astrophysics · Physics 2009-10-30 John P. Ralston , Pankaj Jain

Ellipsometry is a powerful and well-established optical technique used in the characterisation of materials. It works by combining the components of elliptically polarized light in order to draw information about the optical system. We…

Optics · Physics 2018-03-15 Manoel P. Araújo , Stefano De Leo , Gabriel G. Maia