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Images of near-field SAR contains spatial-variant sidelobes and clutter, subduing the image quality. Current image restoration methods are only suitable for small observation angle, due to their assumption of 2D spatial-invariant…

Signal Processing · Electrical Eng. & Systems 2022-10-06 Wensi Zhang , Xiaoling Zhang , Xu Zhan , Yuetonghui Xu , Jun Shi , Shunjun Wei

We present a blind multiframe image-deconvolution method based on robust statistics. The usual shortcomings of iterative optimization of the likelihood function are alleviated by minimizing the M-scale of the residuals, which achieves more…

Instrumentation and Methods for Astrophysics · Physics 2017-11-09 Matthias Lee , Tamas Budavari , Richard White , Charles Gulian

Photometric measurements allow the determination of an asteroid's absolute magnitude, which often represents the sole means to infer its size. Photometric observations can be obtained in a variety of filters that can be unique to a specific…

Earth and Planetary Astrophysics · Physics 2024-11-12 Tobias Hoffmann , Marco Micheli , Juan Luis Cano , Maxime Devogèle , Davide Farnocchia , Petr Pravec , Peter Vereš , Björn Poppe

Although many exoplanets have been indirectly detected over the last years, direct imaging of them with ground-based telescopes remains challenging. In the presence of atmospheric fluctuations, it is ambitious to resolve the high brightness…

Instrumentation and Methods for Astrophysics · Physics 2023-02-08 Jakob Roth , Gianluca Li Causi , Vincenzo Testa , Philipp Arras , Torsten A. Enßlin

We present a method for speckle holography that is optimised for crowded fields. Its two key features are an iterativ improvement of the instantaneous Point Spread Functions (PSFs) extracted from each speckle frame and the (optional)…

Instrumentation and Methods for Astrophysics · Physics 2015-05-30 R. Schoedel , S. Yelda , A. Ghez , J. H. V. Girard , L. Labadie , R. Rebolo , A. Perez-Garrido , M. R. Morris

We present a detailed comparison between simulations and seeing-free observations that takes into account the crucial influence of instrumental image degradation. We use images of quiet Sun granulation taken in the blue, green and red…

Solar and Stellar Astrophysics · Physics 2015-05-13 Sven Wedemeyer-Böhm , Luc Rouppe van der Voort

Like the ordinary power spectrum, higher-order spectra (HOS) describe signal properties that are invariant under translations in time. Unlike the power spectrum, HOS retain phase information from which details of the signal waveform can be…

Signal Processing · Electrical Eng. & Systems 2019-08-27 Christopher K. Kovach , Matthew A. Howard

High-contrast imaging from space must overcome two major noise sources to successfully detect a terrestrial planet angularly close to its parent star: photon noise from diffracted star light, and speckle noise from star light scattered by…

Astrophysics · Physics 2009-11-13 Pascal J. Borde , Wesley A. Traub

Removing speckle noise from medical ultrasound images while preserving image features without introducing artifact and distortion is a major challenge in ultrasound image restoration. In this paper, we propose a multiframe-based adaptive…

Image and Video Processing · Electrical Eng. & Systems 2021-09-30 Jayanta Dey , Md. Kamrul Hasan

The estimation and compensation of quasi-static aberrations is mandatory to reach the ultimate performance of high-contrast imaging systems. COFFEE is a focal plane wave-front sensing method that consists in the extension of phase diversity…

Instrumentation and Methods for Astrophysics · Physics 2015-06-17 B. Paul , L. M. Mugnier , J. -F. Sauvage , K. Dohlen

Future large space- or ground-based telescopes will offer the resolution and sensitivity to probe the habitable zone of a large sample of nearby stars for exo-Earth imaging. To this end, such facilities are expected to be equipped with a…

Instrumentation and Methods for Astrophysics · Physics 2020-10-12 M. Beaulieu , P. Martinez , L. Abe , C. Gouvret , P. Baudoz , R. Galicher

Stacking analysis is a means of detecting faint sources using a priori position information to estimate an aggregate signal from individually undetected objects. Confusion severely limits the effectiveness of stacking in deep surveys with…

Instrumentation and Methods for Astrophysics · Physics 2015-05-14 Peter Kurczynski , Eric Gawiser

Removing camera motion blur from a single light field is a challenging task since it is highly ill-posed inverse problem. The problem becomes even worse when blur kernel varies spatially due to scene depth variation and high-order camera…

Computer Vision and Pattern Recognition · Computer Science 2018-06-15 Dongwoo Lee , Haesol Park , In Kyu Park , Kyoung Mu Lee

We present a new processing technique aimed at significantly improving the angular differential imaging method (ADI) in the context of high-contrast imaging of faint objects nearby bright stars in observations obtained with extreme adaptive…

Instrumentation and Methods for Astrophysics · Physics 2017-11-15 Gianluca Li Causi , Marco Stangalini , Simone Antoniucci , Fernando Pedichini , Massimiliano Mattioli , Vincenzo Testa

Near-diffraction limited imaging and spectroscopy in the visible on large (8-10 meter) class telescopes has proved to be beyond the capabilities of current adaptive optics technologies, even when using laser guide stars. The need for high…

Instrumentation and Methods for Astrophysics · Physics 2015-05-19 Craig Mackay , Tim D. Staley , David King , Frank Suess , Keith Weller

I propose a spatial-mode demultiplexing (SPADE) measurement scheme for the far-field imaging of spatially incoherent optical sources. For any object too small to be resolved by direct imaging under the diffraction limit, I show that SPADE…

Optics · Physics 2017-03-01 Mankei Tsang

I present a semiclassical analysis of a spatial-mode demultiplexing (SPADE) measurement scheme for far-field incoherent optical imaging under the effects of diffraction and photon shot noise. Building on previous results that assume two…

Optics · Physics 2018-02-28 Mankei Tsang

In this article, we provide an alternative up-sampling and PSF deconvolution method for the iterative multi-exposure coaddition. Different from the previous works, the new method has a ratio-correction term, which allows the iterations to…

Instrumentation and Methods for Astrophysics · Physics 2022-10-26 Lei Wang , Guoliang Li , Xi Kang

In this paper we propose a blind deconvolution method which applies to data perturbed by Poisson noise. The objective function is a generalized Kullback-Leibler divergence, depending on both the unknown object and unknown point spread…

Instrumentation and Methods for Astrophysics · Physics 2013-11-25 M. Prato , A. La Camera , S. Bonettini , M. Bertero

The resolution of optical imaging is classically limited by the width of the point-spread function, which in turn is determined by the Rayleigh length. Recently, spatial-mode demultiplexing (SPADE) has been proposed as a method to achieve…

Quantum Physics · Physics 2025-02-26 Giuseppe Buonaiuto , Cosmo Lupo