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The detection of molecular species in the atmospheres of earth-like exoplanets orbiting nearby stars requires an optical system that suppresses starlight and maximizes the sensitivity to the weak planet signals at small angular separations.…

Instrumentation and Methods for Astrophysics · Physics 2017-08-22 Garreth Ruane , Dimitri Mawet , Jeffrey Jewell , Stuart Shaklan

Atmospheric turbulence causes fluctuations in the local refractive index of air that accumulatively disturb a wave's phase and amplitude distribution as it propagates. This impairs the effective range of laser weapons as well as the…

Optics · Physics 2015-06-02 Chensheng Wu , Jonathan Ko , Christopher C. Davis

The Santa Cruz Extreme AO Lab (SEAL) testbed is an optical bench meant to design and develop new wavefront control techniques for high-contrast imaging for segmented telescopes. These techniques allow for astronomical efficiency in…

Instrumentation and Methods for Astrophysics · Physics 2024-08-14 Ashai Moreno , Vincent Chambouleyron , Rebecca M. Jensen-Clem , Daren Dillon , Philip M. Hinz , Bruce Macintosh

We report a novel generalized optical measurement system and computational approach to determine and correct aberrations in optical systems. We developed a computational imaging method capable of reconstructing an optical system's…

Image and Video Processing · Electrical Eng. & Systems 2019-01-10 Jaebum Chung , Gloria W. Martinez , Karen Lencioni , Srinivas Sadda , Changhuei Yang

A lower bound on unbiased estimates of wavefront errors (WFE) is presented for the linear regime of small perturbation and active control of a high-contrast region (dark hole). Analytical approximations and algorithms for computing the…

Instrumentation and Methods for Astrophysics · Physics 2021-10-13 Leonid Pogorelyuk , Laurent Pueyo , Jared R. Males , Kerri Cahoy , N. Jeremy Kasdin

A key challenge of high contrast imaging (HCI) is to differentiate a speckle from an exoplanet signal. The sources of speckles are a combination of atmospheric residuals and aberrations in the non-common path. Those non-common path…

Cardiac segmentation of atriums, ventricles, and myocardium in computed tomography (CT) images is an important first-line task for presymptomatic cardiovascular disease diagnosis. In several recent studies, deep learning models have shown…

Image and Video Processing · Electrical Eng. & Systems 2024-10-01 Sanguk Park , Minyoung Chung

The specification of polishing requirements for the optics in coronagraphs dedicated to exo-planet detection requires careful and accurate optical modelling. Numerical representations of the propagation of aberrations through the system as…

Instrumentation and Methods for Astrophysics · Physics 2011-11-07 Laurent Pueyo , N. Jeremy Kasdin , Stuart Shaklan

Context. Phase-mask coronagraphy is advantageous in terms of inner working angle and discovery space. It is however still plagued by drawbacks such as sensitivity to tip-tilt errors and chromatism. A nulling stellar coronagraph based on the…

Instrumentation and Methods for Astrophysics · Physics 2015-06-11 P. Bourget , N. Schuhler , D. Mawet , P. Haguenauer

Deep learning methods have reached state-of-the-art performance in cardiac image segmentation. Currently, the main bottleneck towards their effective translation into clinics requires assuring continuous high model performance and…

Image and Video Processing · Electrical Eng. & Systems 2021-06-15 Francesco Galati , Maria A. Zuluaga

This paper presents an application of the TwO-Dimensional CORrelation (TODCOR) algorithm to multi-order spectra. The combination of many orders enables the detection and measurement of the radial velocities of very faint companions. The…

Astrophysics · Physics 2007-05-23 S. Zucker , T. Mazeh , N. C. Santos , S. Udry , M. Mayor

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…

The ability to map left ventricle (LV) myocardial motion using computed tomography angiography (CTA) is essential to diagnosing cardiovascular conditions and guiding interventional procedures. Due to their inherent locality, conventional…

Image and Video Processing · Electrical Eng. & Systems 2024-11-08 Shahar Zuler , Shai Tejman-Yarden , Dan Raviv

Precision contouring control is crucial in industrial machining processes, particularly for applications such as laser and water jet cutting, where contouring accuracy directly determines product quality. This paper presents a novel control…

Systems and Control · Electrical Eng. & Systems 2026-04-14 Meng Yuan , Tianyou Chai

The accumulation of aberrations along the optical path in a telescope produces distortions and speckles in the resulting images, limiting the performance of cameras at high angular resolution. It is important to achieve the highest possible…

Instrumentation and Methods for Astrophysics · Physics 2021-03-17 Benjamin J. S. Pope , Laurent Pueyo , Yinzi Xin , Peter G. Tuthill

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 this paper, we propose a unified procedure for calibration of macroscopic second-order multilane traffic models. The focus is on calibrating the fundamental diagram using the combination stationary detector data and GPS traces. GPS…

We report on the performance of a vector apodizing phase plate coronagraph that operates over a wavelength range of $2-5 \mu$m and is installed in MagAO/Clio2 at the 6.5 m Magellan Clay telescope at Las Campanas Observatory, Chile. The…

Aims. We present a solution to improve the performance of coronagraphs for the detection of exo-planets. Methods. We simulate numerically several kinds of coronagraphic systems, with the aim of evaluating the gain obtained with an adaptive…

Instrumentation and Methods for Astrophysics · Physics 2009-07-03 D. Ricci , H. Le Coroller , A. Labeyrie

One of the main limitations of utilizing optimal wavefront shaping in imaging and authentication applications is the slow speed of the optimization algorithms currently being used. To address this problem we develop a micro-genetic…