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Instrumental aberrations strongly limit high-contrast imaging of exoplanets, especially when they produce quasistatic speckles in the science images. With the help of recent advances in deep learning, we have developed in previous works an…

Instrumentation and Methods for Astrophysics · Physics 2022-11-14 Maxime Quesnel , Gilles Orban de Xivry , Olivier Absil , Gilles Louppe

The principal limitation in many areas of astronomy, especially for directly imaging exoplanets, arises from instability in the point spread function (PSF) delivered by the telescope and instrument. To understand the transfer function, it…

Instrumentation and Methods for Astrophysics · Physics 2021-09-01 Alison Wong , Benjamin Pope , Louis Desdoigts , Peter Tuthill , Barnaby Norris , Chris Betters

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

Shack Hartmann wavefront sensor is a two dimensional array of lenslets which is used to detect the incoming phase distorted wavefront through local tilt measurements made by recording the spot pattern near the focal plane. Wavefront…

Instrumentation and Methods for Astrophysics · Physics 2011-08-16 Akondi Vyas , M B Roopashree , B Raghavendra Prasad

Reconstruction techniques are commonly used in cosmology to reduce complicated nonlinear behaviours to a more tractable linearized system. We study a new reconstruction technique that uses the Moving-Mesh algorithm to estimate the…

Cosmology and Nongalactic Astrophysics · Physics 2017-06-21 Qiaoyin Pan , Ue-Li Pen , Derek Inman , Hao-Ran Yu

Diffusion models have achieved remarkable progress in generative modelling, particularly in enhancing image quality to conform to human preferences. Recently, these models have also been applied to low-level computer vision for…

Computer Vision and Pattern Recognition · Computer Science 2025-10-09 Ziwei Luo , Fredrik K. Gustafsson , Zheng Zhao , Jens Sjölund , Thomas B. Schön

We have designed a plenoptic sensor to retrieve phase and amplitude changes resulting from a laser beam's propagation through atmospheric turbulence. Compared with the commonly restricted domain of (-pi, pi) in phase reconstruction by…

Optics · Physics 2023-07-19 Chensheng Wu , Jonathan Ko , Christopher C. Davis

This paper presents a new algorithm, Accelerated Wirtinger Flow (AWF), for ptychographic image reconstruction from phaseless diffraction pattern measurements. AWF is based on combining Nesterov's acceleration approach with Wirtinger…

Image and Video Processing · Electrical Eng. & Systems 2018-06-29 Rui Xu , Mahdi Soltanolkotabi , Justin P. Haldar , Walter Unglaub , Joshua Zusman , Anthony F. J. Levi , Richard M. Leahy

In many practical applications of long-range imaging such as biometrics and surveillance, thermal imagining modalities are often used to capture images in low-light and nighttime conditions. However, such imaging systems often suffer from…

Computer Vision and Pattern Recognition · Computer Science 2022-04-08 Kangfu Mei , Yiqun Mei , Vishal M. Patel

Recently, the joint design of optical systems and downstream algorithms is showing significant potential. However, existing rays-described methods are limited to optimizing geometric degradation, making it difficult to fully represent the…

Computer Vision and Pattern Recognition · Computer Science 2024-12-24 Zheng Ren , Jingwen Zhou , Wenguan Zhang , Jiapu Yan , Bingkun Chen , Huajun Feng , Shiqi Chen

We present a fast and simple technique to convert images into a radiance surface-based scene representation. Building on existing radiance volume reconstruction algorithms, we introduce a subtle yet impactful modification of the loss…

Synthetic aperture sonar (SAS) image resolution is constrained by waveform bandwidth and array geometry. Specifically, the waveform bandwidth determines a point spread function (PSF) that blurs the locations of point scatterers in the…

Computer Vision and Pattern Recognition · Computer Science 2021-12-17 Albert Reed , Thomas Blanford , Daniel C. Brown , Suren Jayasuriya

The photon density operator function is used to calculate light beam propagation through turbulent atmosphere. A kinetic equation for the photon distribution function is derived and solved using the method of characteristics. Optical wave…

Quantum Physics · Physics 2009-11-13 G. P. Berman , A. A. Chumak

It remains a challenge to simultaneously remove geometric distortion and space-time-varying blur in frames captured through a turbulent atmospheric medium. To solve, or at least reduce these effects, we propose a new scheme to recover a…

Computer Vision and Pattern Recognition · Computer Science 2014-01-20 Yuan Xie , Wensheng Zhang , Dacheng Tao , Wenrui Hu , Yanyun Qu , Hanzi Wang

The aim of this paper is to establish a nonlinear variational approach to the reconstruction of moving density images from indirect dynamic measurements. Our approach is to model the dynamics as a hyperelastic deformation of an initial…

Numerical Analysis · Mathematics 2015-12-01 Martin Burger , Jan Modersitzki , Sebastian Suhr

Ground-based solar image restoration is a computationally expensive procedure that involves nonlinear optimization techniques. The presence of atmospheric turbulence produces perturbations in individual images that make it necessary to…

Instrumentation and Methods for Astrophysics · Physics 2023-07-26 A. Asensio Ramos , S. Esteban Pozuelo , C. Kuckein

Deep learning technique has dramatically boosted the performance of face alignment algorithms. However, due to large variability and lack of samples, the alignment problem in unconstrained situations, \emph{e.g}\onedot large head poses,…

Computer Vision and Pattern Recognition · Computer Science 2020-06-26 Xiehe Huang , Weihong Deng , Haifeng Shen , Xiubao Zhang , Jieping Ye

Image subtraction in astronomy is a tool for transient object discovery and characterization, particularly useful in wide fields, and is well suited for moving or photometrically varying objects such as asteroids, extra-solar planets and…

Instrumentation and Methods for Astrophysics · Physics 2013-01-09 Steven Hartung

We design an optical feedback network making use of machine learning techniques and demonstrate via simulations its ability to correct for the effects of turbulent propagation on optical modes. This artificial neural network scheme only…

Signal Processing · Electrical Eng. & Systems 2018-06-22 Sanjaya Lohani , Ryan T. Glasser

We study the problem of deconvolution for light-sheet microscopy, where the data is corrupted by spatially varying blur and a combination of Poisson and Gaussian noise. The spatial variation of the point spread function (PSF) of a…

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