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In ghost imaging scheme, an illuminated light is split into test and reference beams which pass through two different optical systems respectively and an image is constructed by the second-order correlation between the two light beams.…

Multiview photometric stereo (MVPS) seeks to recover high-fidelity surface shapes and reflectances from images captured under varying views and illuminations. However, existing MVPS methods often require controlled darkroom settings for…

Computer Vision and Pattern Recognition · Computer Science 2025-08-07 Songyun Yang , Yufei Han , Jilong Zhang , Kongming Liang , Peng Yu , Zhaowei Qu , Heng Guo

In the present paper we demonstrate the approach of using a holographic grating on a freeform surface for advanced spectrographs design. We discuss the surface and groove pattern description used for ray-tracing. Moreover, we present a…

Instrumentation and Methods for Astrophysics · Physics 2019-09-04 Eduard R. Muslimov , Marc Ferrari , Emmanuel Hugot , Jean-Claude Bouret , Coralie Neiner , Simona Lombardo , Gerard Lemaitre , Robert Grange , Ilya A. Guskov

In the last few years,the field of ghost imaging has seen many new developments. From computational ghost imaging to 3D ghost imaging, this field has shown many interesting applications. But the method of obtaining an image in ghost imaging…

Optics · Physics 2014-06-06 Nandan Jha

Ptychography is a computational imaging technique that aims to reconstruct the object of interest from a set of diffraction patterns. Each of these is obtained by a localized illumination of the object, which is shifted after each…

Image and Video Processing · Electrical Eng. & Systems 2024-02-26 Oleh Melnyk , Patricia Römer

Using five independent analytic and Monte Carlo simulation codes, we have studied the performance of wide field ground layer adaptive optics (GLAO), which can use a single, relatively low order deformable mirror to correct the wavefront…

Light interreflections occurring in a concave object generate a color gradient which is characteristic of the object's spectral reflectance. In this paper, we use this property in order to estimate the spectral reflectance of matte,…

Computer Vision and Pattern Recognition · Computer Science 2018-07-04 Rada Deeb , Damien Muselet , Mathieu Hebert , Alain Tremeau

Future observatories utilizing reflection grating spectrometers for extreme ultraviolet (EUV) and soft X-ray (SXR) spectroscopy require high-fidelity gratings with both blazed groove facets and custom groove layouts that are often fanned or…

Instrumentation and Methods for Astrophysics · Physics 2020-03-17 Jake A. McCoy , Randall L. McEntaffer , Drew M. Miles

The kilo-Hertz gravitational waves radiated by the neutron star merger remnants carry rich information about the physics of high-density nuclear matter states, and many important astrophysical phenomena such as gamma-ray bursts and black…

General Relativity and Quantum Cosmology · Physics 2022-11-08 Chuming Wang , Chunnong Zhao , Xiang Li , Enping Zhou , Haixing Miao , Yanbei Chen , Yiqiu Ma

While the presence of ghosts has been known for decades, the impact of these apparitions on remote sensing observations has gone unquantified, leaving atmospheric corrections susceptible to ghosting. In this work, we present the first…

Popular Physics · Physics 2021-04-02 Marianne Cowherd , Isaac Malsky

Astronomical images are often plagued by unwanted artifacts that arise from a number of sources including imperfect optics, faulty image sensors, cosmic ray hits, and even airplanes and artificial satellites. Spurious reflections (known as…

Instrumentation and Methods for Astrophysics · Physics 2021-05-28 Chihway Chang , Alex Drlica-Wagner , Stephen M. Kent , Brian Nord , Donah Michelle Wang , Michael H. L. S. Wang

We investigate photon tunneling in a pair of coupled inverted circular split-ring microwave resonators with four discrete chiral orientations. By varying the spacing between the resonators, we observe strong modulation of the transmission…

X-ray interferometry is an emerging imaging modality with a wide variety of potential clinical applications, including lung and breast imaging, as well as in non-destructive testing, such as additive manufacturing and porosimetry. A grating…

The perturbations in the electron number density during recombination contributes to the Cosmic Microwave Background bispectrum through second order terms. Perturbations in the electron density can be a factor of ~5 larger than the baryon…

Astrophysics · Physics 2010-04-21 Rishi Khatri , Benjamin D. Wandelt

Ghost imaging enables the imaging of an object using intensity correlations between a single-pixel detector placed behind the object and a camera that records light that did not interact with the object. The object and the camera are often…

Optics · Physics 2025-06-12 Edward Tananyan , Ohad Lib , Michal Zimmerman , Yaron Bromberg

The redshifted 1420 MHz emission from the HI in unresolved damped Lyman-\alpha clouds at high z will appear as a background radiation in low frequency radio observations. This holds the possibility of a new tool for studying the universe at…

Astrophysics · Physics 2009-10-31 Somnath Bharadwaj , Biman B. Nath , Shiv K. Sethi

Lithium Niobate on Sapphire (LNOS) is an emerging platform for photonic integrated circuits, offering unique properties such as a wide transparency window, high nonlinearity, and strong electro-optic, nonlinear, and acousto-optic effects.…

Ghost imaging is a technique -- first realized in quantum optics -- in which the image emerges from cross-correlation between particles in two separate beams. One beam passes through the object to a bucket (single-pixel) detector, while the…

Ghost imaging needs massive measurements to obtain an image with good visibility and the imaging speed is usually very low. In order to realize real-time high-resolution ghost imaging of a target which is located in a scenario with a large…

Image and Video Processing · Electrical Eng. & Systems 2019-05-22 Cheng Zhou , Tian Tian , Chao Gao , Wenli Gong , Lijun Song

We present the results of an experimental study of an advanced moderate-resolution spectrograph based on a cascade of narrow-band holographic gratings. The main goal of the project is to achieve a moderately high spectral resolutionwith R…

Instrumentation and Methods for Astrophysics · Physics 2018-05-22 Eduard Muslimov , Gennady Valyavin , Sergei Fabrika , Faig Musaev , Gazinur Galazutdinov , Nadezhda Pavlycheva , Eduard Emelyanov