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We propose a transmission-filter coronagraph for direct imaging of Jupiter-like exoplanets with ground-based telescopes. The coronagraph is based on a transmission filter that consists of finite number of transmission steps. A discrete…

天体物理仪器与方法 · 物理学 2015-10-14 Deqing Ren , Jiangpei Dou , Yongtian Zhu

This contribution deals with image restoration in optical systems with coherent illumination, which is an important topic in astronomy, coherent microscopy and radar imaging. Such optical systems suffer from wavefront distortions, which are…

天体物理仪器与方法 · 物理学 2017-04-04 Claudius Zelenka , Reinhard Koch

The Astro2020 decadal survey recommended an infrared, optical, ultra-violet (IR/O/UV) telescope with a $\sim$6~m inscribed diameter and equipped with a coronagraph instrument to directly image exoEarths in the habitable zone of their host…

Cardiac MRI segmentation plays a crucial role in clinical diagnosis for evaluating personalized cardiac performance parameters. Due to the indistinct boundaries and heterogeneous intensity distributions in the cardiac MRI, most existing…

计算机视觉与模式识别 · 计算机科学 2020-07-23 Feng Cheng , Cheng Chen , Yukang Wang , Heshui Shi , Yukun Cao , Dandan Tu , Changzheng Zhang , Yongchao Xu

Over the last decade, the vector-apodizing phase plate (vAPP) coronagraph has been developed from concept to on-sky application in many high-contrast imaging systems on 8-m class telescopes. The vAPP is an geometric-phase patterned…

Classification is one of the core problems in Computer-Aided Diagnosis (CAD), targeting for early cancer detection using 3D medical imaging interpretation. High detection sensitivity with desirably low false positive (FP) rate is critical…

计算机视觉与模式识别 · 计算机科学 2014-05-20 Meizhu Liu , Le Lu , Xiaojing Ye , Shipeng Yu

A high contrast coronagraph is expected to provide one of the promising ways to directly observe extra-solar planets. We present the newest results of our laboratory experiment investigating "rigid" coronagraph with a binary shaped…

天体物理仪器与方法 · 物理学 2011-08-17 K. Enya , L. Abe , S. Tanaka , T. Nakagawa , K. Haze , T. Sato , T. Wakayama

The Graph Isomorphism problem has both theoretical and practical interest. In this paper we present an algorithm, called conauto-1.2, that efficiently tests whether two graphs are isomorphic, and finds an isomorphism if they are. This…

数据结构与算法 · 计算机科学 2011-06-23 Jose Luis Lopez-Presa , Antonio Fernandez Anta

Adaptive optic (AO) systems delivering high levels of wavefront correction are now common at observatories. One of the main limitations to image quality after wavefront correction comes from atmospheric refraction. An Atmospheric dispersion…

Successive quadratic approximations, or second-order proximal methods, are useful for minimizing functions that are a sum of a smooth part and a convex, possibly nonsmooth part that promotes regularization. Most analyses of iteration…

最优化与控制 · 数学 2019-01-25 Ching-pei Lee , Stephen J. Wright

Direct detection and spectroscopy of exoplanets requires high contrast imaging. For habitable exoplanets in particular, located at small angular separation from the host star, it is crucial to employ small inner working angle (IWA)…

天体物理仪器与方法 · 物理学 2016-11-09 P. Pathak , O. Guyon , N. Jovanovic , J. Lozi , F. Martinache , Y. Minowa , T. Kudo , H. Takami , Y. Hayano , N. Narita

The raw coronagraphic performance of current high-contrast imaging instruments is limited by the presence of a quasi-static speckle (QSS) background, resulting from instrumental non-common path errors (NCPEs). Rapid development of efficient…

天体物理仪器与方法 · 物理学 2017-01-18 Michael J. Wilby , Christoph U. Keller , Frans Snik , Visa Korkiakoski , Alexander G. M. Pietrow

We performed an experimental verification of a coronagraph. As a result, we confirmed that, at the focal region where the planetary point spread function exists, the coronagraph system mitigates the raw contrast of a star-planet system by…

地球与行星天体物理 · 物理学 2023-07-12 Satoshi Itoh , Taro Matsuo , Shunsuke Ota , Kensuke Hara , Yuji Ikeda , Reiki Kojima , Toru Yamada , Takahiro Sumi

Just how fast does the brickwork circuit form an approximate 2-design? Is there any difference between anticoncentration and being a 2-design? Does geometry matter? How deep a circuit will I need in practice? We tell you everything you…

量子物理 · 物理学 2025-10-29 Daniel Belkin , James Allen , Bryan K. Clark

The detection and characterization of Earth-like exoplanets around Sun-like stars for future flagship missions requires coronagraphs to achieve contrasts on the order of 1e-10 at close angular separations and over large spectral bandwidths…

We present methods for optimizing pupil and focal plane optical elements that improve the performance of vortex coronagraphs on telescopes with obstructed or segmented apertures. Phase-only and complex masks are designed for the entrance…

CONTEXT: The four-quadrant phase mask stellar coronagraph, introduced by D. Rouan et al., is capable of achieving very high dynamical range imaging and was studied in the context of the direct detection of extra-solar planets. Achromatic…

We propose a solution to the problem of astrometric and photometric calibration of coronagraphic images with a simple optical device which, in theory, is easy to use. Our design uses the Fraunhofer approximation of Fourier optics. Placing a…

天体物理学 · 物理学 2008-11-26 Anand Sivaramakrishnan , Ben R. Oppenheimer

Fast Fourier Transform based phase screen simulations give accurate results only when the screen size ($G$) is much larger than the outer scale parameter ($L_0$). Otherwise, they fall short in correctly predicting both the low and high…

天体物理仪器与方法 · 物理学 2021-06-03 Sorabh Chhabra , Jyotirmay Paul , Anamparambu N. Ramaprakash , Avinash Surendran

Adaptive optics (AO) is a powerful tool to increase the imaging depth of multiphoton scanning microscopes. For highly scattering tissues, sensorless wavefront correction techniques exhibit robust performance and present a straight-forward…