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High performance coronagraphic imaging of faint structures around bright stars at small angular separations requires fine control of tip, tilt and other low order aberrations. When such errors occur upstream of a coronagraph, they results…

Instrumentation and Methods for Astrophysics · Physics 2015-06-19 Garima Singh , Frantz Martinache , Pierre Baudoz , Olivier Guyon , Taro Matsuo , Nemanja Jovanovic , Christophe Clergeon

In recent years, convolutional neural networks have demonstrated promising performance in a variety of medical image segmentation tasks. However, when a trained segmentation model is deployed into the real clinical world, the model may not…

Image and Video Processing · Electrical Eng. & Systems 2020-12-24 Shuo Wang , Giacomo Tarroni , Chen Qin , Yuanhan Mo , Chengliang Dai , Chen Chen , Ben Glocker , Yike Guo , Daniel Rueckert , Wenjia Bai

High-precision ground-based observations of the inner corona (1.05-2.0 R_sun) are fundamentally constrained by instrumental stray light, particularly the additive background from dynamic dust accumulation on the objective lens. To address…

Solar and Stellar Astrophysics · Physics 2026-05-14 Xiande Liu , Xuefei Zhang , Yu Liu , Tengfei Song , Mingyu Zhao , Mingzhe Sun , Feiyang Sha , Jun Fang

Deep sub-diffraction exoplanet discovery currently lies beyond the reach of state-of-the-art direct imaging coronagraphs, which typically have an inner working angle larger than the diffraction scale. We present an experimental…

Instrumentation and Methods for Astrophysics · Physics 2025-05-06 Nico Deshler , Itay Ozer , Amit Ashok , Saikat Guha

Magnetic field is the key physical quantity in solar physics as it controls all kinds of solar activity, ranging from nanoflares to big flares and coronal mass ejections (CMEs). However, so far only the magnetic field on the solar surface…

Solar and Stellar Astrophysics · Physics 2025-11-21 P. F. Chen

Interpreting the mineralogical aspects of rock thin sections is an important task for oil and gas reservoirs evaluation. However, human analysis tend to be subjective and laborious. Technologies like QEMSCAN(R) are designed to automate the…

The final performance of current and future instruments dedicated to exoplanet detection and characterization (such as SPHERE on the European Very Large Telescope, GPI on Gemini North, or future instruments on Extremely Large Telescopes) is…

Instrumentation and Methods for Astrophysics · Physics 2015-06-15 B. Paul , L. M. Mugnier , J. -F. Sauvage

We propose a coronagraphic system with fourth-order null for off-axis segmented telescopes, which is sufficiently insensitive to the telescope pointing errors and finite angular diameter of the host star to enable high-contrast imaging of…

Instrumentation and Methods for Astrophysics · Physics 2020-05-06 Satoshi Itoh , Taro Matsuo

Imaging terrestrial exoplanets around nearby stars is a formidable technical challenge, requiring the development of coronagraphs to suppress the stellar halo of diffracted light at the location of the planet. In this review, we derive the…

Instrumentation and Methods for Astrophysics · Physics 2025-06-04 Matthew A. Kenworthy , Sebastiaan Y. Haffert

A vortex coronagraph is now available for high contrast observations with the Keck/NIRC2 instrument at L band. Reaching the optimal performance of the coronagraph requires fine control of the wavefront incident on the phase mask. In…

Instrumentation and Methods for Astrophysics · Physics 2017-03-29 Elsa Huby , Michael Bottom , Bruno Femenia , Henry Ngo , Dimitri Mawet , Eugene Serabyn , Olivier Absil

Stellar coronagraphs rely on deformable mirrors (DMs) to correct wavefront errors and create high contrast images. Imperfect control of the DM limits the achievable contrast and, therefore, the DM control electronics must provide fine…

Direct detection of exoplanets requires high dynamic range imaging. Coronagraphs could be the solution, but their performance in space is limited by wavefront errors (manufacturing errors on optics, temperature variations, etc.), which…

Instrumentation and Methods for Astrophysics · Physics 2015-05-14 Raphael Galicher , Pierre Baudoz , Gerard Rousset , Julien Totems , Marion Mas

We review methods to measure magnetic fields within the corona using the polarized light in magnetic-dipole (M1) lines. We are particularly interested in both the global magnetic-field evolution over a solar cycle, and the local storage of…

Solar and Stellar Astrophysics · Physics 2015-06-15 Philip G. Judge , Shadia Habbal , Enrico Landi

Coronagraph instruments on future space telescopes will enable the direct detection and characterization of Earth-like exoplanets around Sun-like stars for the first time. The quest for the optimal optical coronagraph designs has made rapid…

Instrumentation and Methods for Astrophysics · Physics 2018-08-30 G. Ruane , A. Riggs , C. T. Coker , S. B. Shaklan , E. Sidick , D. Mawet , J. Jewell , K. Balasubramanian , C. C. Stark

Feature tracking Cardiac Magnetic Resonance (CMR) has recently emerged as an area of interest for quantification of regional cardiac function from balanced, steady state free precession (SSFP) cine sequences. However, currently available…

Computer Vision and Pattern Recognition · Computer Science 2017-04-13 Davis M. Vigneault , Weidi Xie , David A. Bluemke , J. Alison Noble

Each year, numerous segmentation and classification algorithms are invented or reused to solve problems where machine vision is needed. Generally, the efficiency of these algorithms is compared against the results given by one or many human…

Computer Vision and Pattern Recognition · Computer Science 2008-12-18 Arnaud Martin , Hicham Laanaya , Andreas Arnold-Bos

Future high-contrast imaging spectroscopy with a large segmented telescope will be able to detect atmospheric molecules of Earth-like planets around G- or K-type main-sequence stars. Increasing the number of target planets will require a…

Instrumentation and Methods for Astrophysics · Physics 2022-05-25 Satoshi Itoh , Taro Matsuo

In recent years, a two-dimensional (2D) coronal seismology technique applied to spectral-imaging data from the Coronal Multi-channel Polarimeter (CoMP) and UCoMP has enabled routine measurement of the global coronal magnetic field. The…

Solar and Stellar Astrophysics · Physics 2026-01-16 Zihao Yang , Sarah Gibson , Matthias Rempel , Giuliana de Toma

The WFIRST-AFTA 2.4 m telescope will provide in the next decade the opportunity to host a coronagraph for the imaging and spectroscopy of planets and disks. The telescope, however, is not ideal, given its obscured aperture. Only recently…

Instrumentation and Methods for Astrophysics · Physics 2015-09-18 John Krist , Bijan Nemati , Bertrand Mennesson

The Coronagraph Instrument (CGI) for NASA's Wide Field Infrared Survey Telescope (WFIRST) will constitute a dramatic step forward for high-contrast imaging, integral field spectroscopy, and polarimetry of exoplanets and circumstellar disks,…