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We describe the salient characteristics of Sentinel-1 wave (WV) mode vignettes. We describe our approach for working with WV mode data that enables vignette-based data access and processing, thereby eliminating the Sentinel-1 Single Look…

Image and Video Processing · Electrical Eng. & Systems 2024-06-24 Piyush S. Agram , Matthew T. Calef , Kelly M. Olsen , Kimberly Carlson , Scott Arko

Spatial phase-referencing in dual-field optical interferometry is reconsidered. Our analysis is based on the 2-sample variance of the differential phase between target and reference star. We show that averaging over time of the atmospheric…

Astrophysics · Physics 2009-11-07 Gerard Daigne , Jean-Francois Lestrade

We present the optical and cryo-mechanical solutions for the Spectrograph of VSI (VLTI Spectro-Imager), the second generation near-infrared (J, H and K bands) interferometric instrument for the VLTI. The peculiarity of this spectrograph is…

Astrophysics · Physics 2009-11-13 D. Lorenzetti , G. Li Causi , R. Speziali , F. Vitali , D. Loreggia , C. Baffa , P. Kern , L. Jocou , F. Malbet , P. Rabou

Interferometric observations with three telescopes or more provide two observables: closure phase information together with visibilities measurements. When using single-mode interferometers, both observables have to be redefined in the…

Astrophysics · Physics 2009-11-11 E. Tatulli , A. Chelli

We present a new approach for image reconstruction and weak lensing measurements with interferometers. Based on the shapelet formalism presented in Refregier (2001), object images are decomposed into orthonormal Hermite basis functions. The…

Astrophysics · Physics 2009-11-06 Tzu-Ching Chang , Alexandre Refregier

The presence of stable, compact circumbinary discs of gas and dust around post-asymptotic giant branch (post-AGB) binary systems has been well established. We focus on one such system: IRAS 08544-4431. We present an interferometric…

Solar and Stellar Astrophysics · Physics 2021-06-16 A. Corporaal , J. Kluska , H. Van Winckel , D. Bollen , D. Kamath , M. Min

The 2nd generation VLTI instrument GRAVITY is a two-field infrared interferometer operating in the K band between 1.97 and 2.43 $\mu$m with either the four 8 m or the four 1.8 m telescopes of the Very Large Telescope (VLT). Beams collected…

The use of integral field spectroscopy is becoming increasingly popular, hovewer data reduction is still a difficult process. Here I present a step-by-step guide to the reduction of integral field data acquired with the Gemini Multi-Object…

Instrumentation and Methods for Astrophysics · Physics 2014-09-30 Davide Lena

In the case of vector flow imaging systems, the most employed flow estimation techniques are the directional beamforming based cross correlation and the triangulation-based autocorrelation. However, the directional beamforming-based…

Signal Processing · Electrical Eng. & Systems 2022-06-07 A. N. Madhavanunni , Mahesh Raveendranatha Panicker

Time-Delay Interferometry (TDI) is the data processing technique that cancels the large laser phase fluctuations affecting the one-way Doppler measurements made by unequal-arm space-based gravitational wave interferometers. By taking finite…

General Relativity and Quantum Cosmology · Physics 2022-05-11 Sanjeev Dhurandhar , Prasanna Joshi , Massimo Tinto

Starlight suppression techniques for High-Contrast Imaging (HCI) are crucial to achieving the demanding contrast ratios and inner working angles required for detecting and characterizing exoplanets with a wide range of masses and…

We present computer simulations of interferometric imaging with the Very Large Telescope Interferometer (VLTI) of the European Southern Observatory (ESO) and the Astronomical MultiBEam Recombiner (AMBER) phase-closure instrument. These…

Astrophysics · Physics 2015-06-24 F. Przygodda , T. Bloecker , K. -H. Hofmann , G. Weigelt

Wavefront sensing involves estimating the phase and intensity of light, enabling a wide range of imaging applications, from adaptive optics and astronomy to biomedical imaging. Since conventional image sensors can only measure the spatial…

Image and Video Processing · Electrical Eng. & Systems 2026-04-07 Nebiyou Yismaw , Vishwanath Saragadam , Aswin C. Sankaranarayanan , M. Salman Asif

In this paper we propose a shrinkage wavelet-based method to estimate the signal in a nonparametric regression model with Autoregressive Fractionally Integrated Moving Average (ARFIMA) errors. Monte Carlo experiments indicate that the…

Methodology · Statistics 2025-05-13 Alex Rodrigo dos S. Sousa , Mauricio Zevallos

We propose a method based on sinc series approximations for computing the Rayleigh-Sommerfeld and Fresnel diffraction integrals of optics. The diffraction integrals are given in terms of a convolution, and our proposed numerical approach is…

Computational Physics · Physics 2021-11-16 Max Cubillos , Edwin Jimenez

Recovering images from optical interferometric observations is one of the major challenges in the field. Unlike the case of observations at radio wavelengths, in the optical the atmospheric turbulence changes the phases on a very short time…

For sensitive infrared interferometry, it is crucial to control the differential piston evolution between the used telescopes. This is classically done by the use of a fringe tracker. In this work, we develop a new method to reconstruct the…

Instrumentation and Methods for Astrophysics · Physics 2018-01-31 Felix Widmann , Jörg-Uwe Pott , Sergio Velasco

Despite offering high sensitivity, a high signal-to-noise ratio, and a broad spectral range, single-pixel imaging (SPI) is limited by low measurement efficiency and long data-acquisition times. To address this, we propose a…

Observations at mas-resolution scales and high dynamic range hold a central place in achieving, for instance, the spectroscopic characterization of exo-Earths or the detailed mapping of their protoplanetary disc birthplace. Ground or…

Instrumentation and Methods for Astrophysics · Physics 2015-05-27 Lucas Labadie , Guillermo Martin , Norman C. Anheier , Brahim Arezki , H. A. Qiao , Bruce Bernacki , Pierre Kern

Full waveform inversion (FWI) is used to reconstruct the physical properties of subsurface media which plays an important role in seismic exploration. However, the precision of FWI is seriously affected by the absence or inaccuracy of…

Geophysics · Physics 2024-04-29 Zheng Cong , Xintong Dong , Shaoping Lu , Shiqi Dong , Xunqian Tong