English
Related papers

Related papers: Coronagraph Experiment on Dark-hole Control by Spe…

200 papers

Light-based synthetic aperture (SA) imaging methods, such as Fourier Ptychography, have brought breakthrough high-resolution wide-field-of-view imaging capabilities to microscopy. While these technologies promise similar improvements in…

Optics · Physics 2025-09-29 Janith B. Senanayaka , Christopher A. Metzler

The speckle noise inherent in Synthetic Aperture Radar (SAR) imagery significantly degrades image quality and complicates subsequent analysis. Given that SAR speckle is multiplicative and Gamma-distributed, effectively despeckling SAR…

Image and Video Processing · Electrical Eng. & Systems 2026-01-22 Junhyuk Heo

Directly imaging and characterizing Earth-like exoplanets is a tremendously difficult instrumental challenge. Present coronagraphic systems have yet to achieve the required $10^{-10}$ broadband contrast in a laboratory environment, but…

Instrumentation and Methods for Astrophysics · Physics 2019-07-10 Carl T. Coker , Stuart B. Shaklan , A J E. Riggs , Garreth Ruane

In ground-based high-contrast instruments, non-common path aberrations (NCPAs) limit detection performance, as they are unseen by the adaptive optics (AO) wavefront sensor but impact the astrophysical image, creating quasi-static speckles.…

Instrumentation designed to characterize potentially habitable planets may combine adaptive optics and high-resolution spectroscopy techniques to achieve the highest possible sensitivity to spectral signs of life. Detecting the weak signal…

Instrumentation and Methods for Astrophysics · Physics 2018-11-13 Garreth Ruane , Ji Wang , Dimitri Mawet , Nemanja Jovanovic , Jacques-Robert Delorme , Bertrand Mennesson , J. Kent Wallace

In the field of planet and proto-planetary disk detection, achieving high angular resolution and high dynamic range is a necessity. Coronography coupled with adaptive optics on Hubble Space Telescope is a way to get both good spatial…

Astrophysics · Physics 2007-05-23 Fabien Malbet , Michael Shao , Jeffrey Yu

Context. In the context of direct imaging of exoplanets, coronagraphs are commonly proposed to reach the required very high contrast levels. However, wavefront aberrations induce speckles in their focal plane and limit their performance.…

Instrumentation and Methods for Astrophysics · Physics 2015-06-18 Johan Mazoyer , Pierre Baudoz , Raphaël Galicher , Gérard Rousset

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

Photonic lantern nulling (PLN) is a method for enabling the detection and characterization of close-in exoplanets by exploiting the symmetries of the ports of a mode-selective photonic lantern (MSPL) to cancel out starlight. A six-port MSPL…

The need for high dynamic range imaging is crucial in many astronomical fields, such as extra-solar planet direct detection, extra-galactic science and circumstellar imaging. Using a high quality coronograph, dynamic ranges of up to…

Astrophysics · Physics 2016-08-30 F. Malbet , J. W. Yu , M. Shao

The 2020 Decadal Survey on Astronomy and Astrophysics tasked future space observatories with the goal of detecting and characterizing a large sample of Earth-like exoplanets. To achieve this, these observatories will require coronagraphs…

We revive a cross-platform focal-plane wavefront sensing and control algorithm originally released in 1980 and show that it can provide significant contrast improvements over conventional control methods on coronagraphic instruments. Its…

Instrumentation and Methods for Astrophysics · Physics 2023-04-03 Iva Laginja , Raphaël Pourcelot

Optical imperfections, misalignments, aberrations, and even dust can significantly limit sensitivity in high-contrast imaging systems such as coronagraphs. An upstream deformable mirror (DM) in the pupil can be used to correct or compensate…

Instrumentation and Methods for Astrophysics · Physics 2015-06-15 Johanan L. Codona , Matthew Kenworthy

Vortex fiber nulling is a method for spectroscopically characterizing exoplanets at small angular separations, $\lesssim\lambda/D$, from their host star. The starlight is suppressed by creating an optical vortex in the system point spread…

Instrumentation and Methods for Astrophysics · Physics 2019-05-10 Daniel Echeverri , Garreth Ruane , Nemanja Jovanovic , Dimitri Mawet , Nicolas Levraud

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

Existing visual SLAM approaches are sensitive to illumination, with their precision drastically falling in dark conditions due to feature extractor limitations. The algorithms currently used to overcome this issue are not able to provide…

Imaging exoplanetary systems is essential to characterizing exoplanetary systems and to studying planet-disk interactions to understand planet formation. Such imaging in the visible and near-infrared is challenging because these objects are…

Instrumentation and Methods for Astrophysics · Physics 2024-03-29 Raphael Galicher , Axel Potier , Johan Mazoyer , Zahed Wahhaj , Pierre Baudoz , Gaël Chauvin

Speckle suppression in synthetic aperture radar (SAR) images is a key processing step which continues to be a research topic. A wide variety of methods, using either spatially-based approaches or transform-based strategies, have been…

Computer Vision and Pattern Recognition · Computer Science 2024-08-30 Alejandro Mestre-Quereda , Juan M. Lopez-Sanchez

We present a novel method to synthesize non-trivial speckles that can enable superresolving second-order correlation imaging. The speckles acquire a unique anti-correlation in the spatial intensity fluctuation by introducing the blue noise…

High-contrast imaging for the detection and characterization of exoplanets relies on the instrument's capability to block out the light of the host star. Some current post-processing methods for calibrating out the residual speckles use…

Instrumentation and Methods for Astrophysics · Physics 2015-06-15 Marie Ygouf , Laurent M. Mugnier , David Mouillet , Thierry Fusco , Jean-Luc Beuzit