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Direct imaging of exoplanets is usually limited by quasi-static speckles. These uncorrected aberrations in a star's point spread function (PSF) obscure faint companions and limit the sensitivity of high-contrast imaging instruments. Most…

Instrumentation and Methods for Astrophysics · Physics 2021-05-05 William Thompson , Christian Marois

High-contrast imaging (HCI) is one of the most challenging techniques for exoplanet detection. It relies on sophisticated data processing to reach high contrasts at small angular separations. Most data processing techniques of this type are…

Instrumentation and Methods for Astrophysics · Physics 2021-02-10 Carl-Henrik Dahlqvist , Olivier Absil

Nearby stars offer prime opportunities for exoplanet discovery and characterization through various detection methods. By combining HCI, RV, and astrometry, it is possible to better constrain the presence of substellar companions, as each…

Earth and Planetary Astrophysics · Physics 2025-07-04 L. F. Sartori , M. J. Bonse , Y. Li , F. A. Dannert , S. P. Quanz , A. Boehle

Coherent diffractive imaging (CDI) provides new opportunities for high resolution X-ray imaging with simultaneous amplitude and phase contrast. Extensions to CDI broaden the scope of the technique for use in a wide variety of experimental…

Optics · Physics 2016-01-20 Matthew H. Seaberg , Alexandre d'Aspremont , Joshua J. Turner

Direct imaging of extra-solar planets has now become a reality, especially with the deployment and commissioning of the first generation of specialized ground-based instruments such as the GPI, SPHERE, P1640 and SCExAO. These systems will…

Instrumentation and Methods for Astrophysics · Physics 2015-06-22 Sandrine J. Thomas , Ruslan Belikov , Eduardo Bendek

We present a novel axial ptychographic coherent diffractive imaging (AP-CDI) technique designed to overcome the critical throughput bottleneck of conventional methods. By replacing the 2D raster scan with a simple 1D axial scan, our…

Optics · Physics 2025-11-24 Qijun You , Lingshuo Meng , Fangrui Quan , Wei Cao

Modern imaging techniques at the molecular scale rely on utilizing novel coherent light sources like X-ray free electron lasers for the ultimate goal of visualizing such objects as individual biomolecules rather than crystals. Here, unlike…

The detection of exoplanets in high-contrast imaging (HCI) data hinges on post-processing methods to remove spurious light from the host star. So far, existing methods for this task hardly utilize any of the available domain knowledge about…

Instrumentation and Methods for Astrophysics · Physics 2020-12-10 Timothy D. Gebhard , Markus J. Bonse , Sascha P. Quanz , Bernhard Schölkopf

We present a novel machine-learning approach for detecting faint point sources in high-contrast adaptive optics imaging datasets. The most widely used algorithms for primary subtraction aim to decouple bright stellar speckle noise from…

Instrumentation and Methods for Astrophysics · Physics 2023-12-07 Trevor N. Wolf , Brandon A. Jones , Brendan P. Bowler

Doppler Imaging (DI) is a well-established technique to map a physical field at a stellar surface from a time series of high-resolution spectra. In this proof-of-concept study, we aim to show that traditional DI algorithms, originally…

Image Rotation and Subtraction (IRS) is a high-contrast imaging technique which can be used to suppress the speckles noise and facilitate the direct detection of exoplanets. IRS is different from Angular Differential Imaging (ADI), in which…

Instrumentation and Methods for Astrophysics · Physics 2015-06-23 Jiangpei Dou , Deqing Ren , Gang Zhao , Xi Zhang , Rui Chen , Yongtian Zhu

With over 1,000,000 images from more than 10,000 exposures using state-of-the-art high-contrast imagers (e.g., Gemini Planet Imager, VLT/SPHERE) in the search for exoplanets, can artificial intelligence (AI) serve as a transformative tool…

Earth and Planetary Astrophysics · Physics 2025-06-05 Fangyi Cao , Bin Ren , Zihao Wang , Shiwei Fu , Youbin Mo , Xiaoyang Liu , Yuzhou Chen , Weixin Yao

The NIRC2 vortex coronagraph is an instrument on Keck II designed to directly image exoplanets and circumstellar disks at mid-infrared bands $L^\prime$ (3.4-4.1 $\mu$m) and $M_s$ (4.55-4.8 $\mu$m). We analyze imaging data and corresponding…

The Near-Infrared Coronagraphic Imager (NICI) is a high-contrast AO imager at the Gemini South telescope. The camera includes a coronagraphic mask and dual channel imaging for Spectral Differential Imaging (SDI). The instrument can also be…

Data processing constitutes a critical component of high-contrast exoplanet imaging. Its role is almost as important as the choice of a coronagraph or a wavefront control system, and it is intertwined with the chosen observing strategy.…

Instrumentation and Methods for Astrophysics · Physics 2016-04-20 C. A. Gomez Gonzalez , O. Absil , P. -A. Absil , M. Van Droogenbroeck , D. Mawet , J. Surdej

Using higher-order coherence of thermal light sources, the resolution power of standard x-ray imaging techniques can be enhanced. In this work, we applied the higher-order measurement to far-field x-ray diffraction and near-field phase…

High-contrast imaging observations of large angular diameter stars enable complementary science questions to be addressed compared to the baseline goals of proposed missions like the Terrestrial Planet Finder-Coronagraph, New World's…

Earth and Planetary Astrophysics · Physics 2015-05-14 Justin R. Crepp , Suvrath Mahadevan , Jian Ge

This year, a second generation of coronagraphs dedicated to high-contrast direct imaging of exoplanets is starting operations. Among them, SPHERE, installed at the focus of the UT3 Very Large Telescope, reaches unprecedented contrast ratios…

Instrumentation and Methods for Astrophysics · Physics 2015-10-22 H. Le Coroller , M. Nowak , L. Arnold , K. Dohlen , T. Fusco , J. F. Sauvage , A. Vigan

We explore the possibility of detecting very faint, very close-in stellar companions using large aperture ground-based telescopes and the technique of optical speckle imaging. We examine the state of high angular resolution speckle imaging…

Instrumentation and Methods for Astrophysics · Physics 2024-04-25 Steve B. Howell , Arturo O. Martinez , Douglas A. Hope , David R. Ciardi , Stuart M. Jefferies , Fabien R. Baron , Michael B. Lund

Most of the high-contrast imaging (HCI) data-processing techniques used over the last 15 years have relied on the angular differential imaging (ADI) observing strategy, along with subtraction of a reference point spread function (PSF) to…

Instrumentation and Methods for Astrophysics · Physics 2021-12-08 Carl-Henrik Dahlqvist , Faustine Cantalloube , Olivier Absil