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Image Reconstruction Wave Front Sensing And Adaptive Optics In Extreme Atmospheric Seeing Conditions
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Book Synopsis Image Reconstruction, Wave Front Sensing, and Adaptive Optics in Extreme Atmospheric Seeing Conditions by :
Download or read book Image Reconstruction, Wave Front Sensing, and Adaptive Optics in Extreme Atmospheric Seeing Conditions written by and published by . This book was released on 2008 with total page 13 pages. Available in PDF, EPUB and Kindle. Book excerpt: On June 1, 2005 AFOSR awarded a grant to Michigan Technological University to investigate image reconstruction, wave front sensing, and adaptive optics in extreme imaging conditions. This is the final report for this program. The overall goal was to understand imaging under conditions where seeing is exceedingly poor, such as for space surveillance of objects at very low elevation angles, and during daytime hours. In these situations, scintillation and small isoplanatic angles dominate the image measurement and reconstruction problems. Our work was focused on performing trade-offs in the adaptive optics control algorithms for imaging under conditions of poor seeing arising from large zenith angles. In particular, we have developed a closed loop simulation of an adaptive optics system which is physically similar to the AEOS system, that uses the conventional least squares reconstructor, the exponential reconstruction, and the so-called "slope discrepancy" reconstructor. We have also examined the use of the stochastic parallel gradient descent (SPGD) algorithm for deformable mirror control in problems dominated by scintillation and anisoplanatism, and conducted a laboratory experiment to demonstrate this idea. In this report we document the results. Our work with maximum likelihood-based image reconstruction algorithms has been applied to the results provided by the adaptive optics simulation, and representative results are included here.
Book Synopsis Imaging Through Turbulence by : Michael C. Roggemann
Download or read book Imaging Through Turbulence written by Michael C. Roggemann and published by CRC Press. This book was released on 2018-02-06 with total page 389 pages. Available in PDF, EPUB and Kindle. Book excerpt: Learn how to overcome resolution limitations caused by atmospheric turbulence in Imaging Through Turbulence. This hands-on book thoroughly discusses the nature of turbulence effects on optical imaging systems, techniques used to overcome these effects, performance analysis methods, and representative examples of performance. Neatly pulling together widely scattered material, it covers Fourier and statistical optics, turbulence effects on imaging systems, simulation of turbulence effects and correction techniques, speckle imaging, adaptive optics, and hybrid imaging. Imaging Through Turbulence is written in tutorial style, logically guiding you through these essential topics. It helps you bring down to earth the complexities of coping with turbulence.
Book Synopsis Frame Selection Performance Limits for Statistical Image Reconstruction of Adaptive Optics Compensated Images by :
Download or read book Frame Selection Performance Limits for Statistical Image Reconstruction of Adaptive Optics Compensated Images written by and published by . This book was released on 1994 with total page 200 pages. Available in PDF, EPUB and Kindle. Book excerpt: The U.S. Air Force uses adaptive optics systems to collect images of extended objects beyond the atmosphere. These systems use wavefront sensors and deformable mirrors to compensate for atmospheric turbulence induced aberrations. Adaptive optics greatly enhance image quality, however, wavefront aberrations are not completely eliminated. Therefore, post-detection processing techniques are employed to further improve the compensated images. Typically, many short exposure images are collected, recentered to compensate for tilt, and then averaged to overcome randomness in the images and improve signal-to-noise ratio. Experience shows that some short exposure images in a data set are better than others. Frame selection exploits this fact by using a quality metric to discard low quality frames. A composite image is then created by averaging only the best frames. Performance limits associated with the frame selection technique are investigated in this thesis. Limits imposed by photon noise result in a minimum object brightness of visual magnitude +8 for point sources and +4 for a typical satellite model. Effective average point spread functions for point source and extended objects after frame selection processing are almost identical across a wide range of conditions. This discovery aliows the use of deconvolution techniques to sharpen images after using the frame selection technique. A new post-detection processing method, frame weighting, is investigated and may offer some improvement for dim objects during poor atmospheric seeing. Frame selection is demonstrated for the first time on actual imagery from an adaptive optics system. Data analysis indicates that signal-to-noise ratio improvements are degraded for exposure times longer than that allowed to "freeze" individual realizations of the turbulence effects.
Book Synopsis Wavefront Sensing the 3D Image Reconstruction in Deep Turbulence by : Matthais Thomas Banet
Download or read book Wavefront Sensing the 3D Image Reconstruction in Deep Turbulence written by Matthais Thomas Banet and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: "The work presented in this dissertation explores the use of several unconventional imaging and wavefront sensing modalities in the presence of distributed-volume, or "deep," atmospheric turbulence. This dissertation focuses on the propagation of coherent light from laser sources through the atmosphere, and imaging/wavefront sensing at optical and infrared laser wavelengths. Such wavelengths are negatively affected by deep turbulence. We use a coherent detection method known as digital holography to (1) coherently image distant objects and (2) to sense and correct for aberrations due to turbulence along the propagation path. We showed that compensated-beacon adaptive optics can be used with a digital holographic wavefront sensor or a Shack-Hartmann wavefront sensor to improve the performance of beam projection to distant objects over uncompensated beacon adaptive optics. We saw performance gains of 17% for the Shack-Hartmann wavefront sensor and 26% for the digital holographic wavefront sensor on average for several turbulence scenarios. We explored multi-wavelength 3D imaging with digital holography along with two speckle decorrelation mechanisms that degrade 3D imaging performance in a theoretical framework. Upon establishing this framework, we simulated multi-wavelength 3D imaging of distant objects through deep turbulence and reconstructed the imagery using sharpness metric maximization for 3D data. The results showed that the reconstruction process was more successful if using more corrective phase screens along the digital propagation path. Additionally we showed that sharpness metric maximization suffered in performance in the presence of scintillated illumination patterns, also known as uplink scintillation. Finally we explored motion compensated, multi-wavelength 3D imaging with digital holography and a pilot tone in theory. Our theoretical framework predicted that one would see increased noise in range images, known as range chatter, over highly-sloped object facets relative to the optical axis, and simulations bore this out explicitly. We showed that range chatter increases as a function of object facet slope, optical illumination bandwidth, optical frequency spacing, and turbulence. Going further we used sharpness metric maximization to improve the range chatter that was brought about by turbulence."--Pages xiv-xv.
Book Synopsis Adaptive Beaming and Imaging in the Turbulent Atmosphere by : Vladimir Petrovich Lukin
Download or read book Adaptive Beaming and Imaging in the Turbulent Atmosphere written by Vladimir Petrovich Lukin and published by SPIE Press. This book was released on 2002 with total page 222 pages. Available in PDF, EPUB and Kindle. Book excerpt: Due to the wide application of adaptive optical systems, an understanding of optical wave propagation in randomly inhomogeneous media has become essential, and several numerical models of individual AOS components and of efficient correction algorithms have been developed. This monograph contains detailed descriptions of the mathematical experiments that were designed and carried out during more than a decade's worth of research.
Book Synopsis The Sun as a Guide to Stellar Physics by : Oddbjørn Engvold
Download or read book The Sun as a Guide to Stellar Physics written by Oddbjørn Engvold and published by Elsevier. This book was released on 2018-11-15 with total page 522 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Sun as a Guide to Stellar Physics illustrates the significance of the Sun in understanding stars through an examination of the discoveries and insights gained from solar physics research. Ranging from theories to modeling and from numerical simulations to instrumentation and data processing, the book provides an overview of what we currently understand and how the Sun can be a model for gaining further knowledge about stellar physics. Providing both updates on recent developments in solar physics and applications to stellar physics, this book strengthens the solar–stellar connection and summarizes what we know about the Sun for the stellar, space, and geophysics communities. Applies observations, theoretical understanding, modeling capabilities and physical processes first revealed by the sun to the study of stellar physics Illustrates how studies of Proxima Solaris have led to progress in space science, stellar physics and related fields Uses characteristics of solar phenomena as a guide for understanding the physics of stars
Book Synopsis High Resolution Imaging in Microscopy and Ophthalmology by : Josef F. Bille
Download or read book High Resolution Imaging in Microscopy and Ophthalmology written by Josef F. Bille and published by Springer. This book was released on 2019-08-13 with total page 407 pages. Available in PDF, EPUB and Kindle. Book excerpt: This open access book provides a comprehensive overview of the application of the newest laser and microscope/ophthalmoscope technology in the field of high resolution imaging in microscopy and ophthalmology. Starting by describing High-Resolution 3D Light Microscopy with STED and RESOLFT, the book goes on to cover retinal and anterior segment imaging and image-guided treatment and also discusses the development of adaptive optics in vision science and ophthalmology. Using an interdisciplinary approach, the reader will learn about the latest developments and most up to date technology in the field and how these translate to a medical setting. High Resolution Imaging in Microscopy and Ophthalmology – New Frontiers in Biomedical Optics has been written by leading experts in the field and offers insights on engineering, biology, and medicine, thus being a valuable addition for scientists, engineers, and clinicians with technical and medical interest who would like to understand the equipment, the applications and the medical/biological background. Lastly, this book is dedicated to the memory of Dr. Gerhard Zinser, co-founder of Heidelberg Engineering GmbH, a scientist, a husband, a brother, a colleague, and a friend.
Book Synopsis Adaptive Optics in Astronomy by : François Roddier
Download or read book Adaptive Optics in Astronomy written by François Roddier and published by Cambridge University Press. This book was released on 1999-06-17 with total page 421 pages. Available in PDF, EPUB and Kindle. Book excerpt: Adaptive optics is set to revolutionise the future of astronomy; this is the first book on the subject and is set to become the standard reference.
Book Synopsis Principles Of Adaptive Optics by : Robert Tyson
Download or read book Principles Of Adaptive Optics written by Robert Tyson and published by Academic Press. This book was released on 2012-12-02 with total page 311 pages. Available in PDF, EPUB and Kindle. Book excerpt: Principles of Adaptive Optics covers the basic principles of optics, wavefront sensing, controls, and wavefront correction that encompass the specialized field called adaptive optics. This book is composed of eight chapters that summarize the fundamental technology developments and the basic understanding of the various disciplines used in adaptive optics. After briefly reviewing the history, background, and developments of adaptive optics, this book goes on discussing the many sources of phase aberrations addressed by adaptive optics systems, such as linear effects due to turbulence, optical manufacturing, and misalignments, as well as errors that result from nonlinear thermal effects and fluid properties. The subsequent chapter deals with the performance enhancing role of adaptive optics systems in various disturbances. Other chapters describe the wavefront sampling, sensing, and correction subsystems. The concluding chapters explore the fundamental principles behind the adaptive optics control system and present summary expressions to determine the basic system parameters of an adaptive optics atmospheric compensation system. Communication scientists and engineers will find this work invaluable.
Book Synopsis Adaptive Filter Theory by : Simon S. Haykin
Download or read book Adaptive Filter Theory written by Simon S. Haykin and published by . This book was released on 1996 with total page 1018 pages. Available in PDF, EPUB and Kindle. Book excerpt: Haykin examines both the mathematical theory behind various linear adaptive filters with finite-duration impulse response (FIR) and the elements of supervised neural networks. This edition has been updated and refined to keep current with the field and develop concepts in as unified and accessible a manner as possible. It: introduces a completely new chapter on Frequency-Domain Adaptive Filters; adds a chapter on Tracking Time-Varying Systems; adds two chapters on Neural Networks; enhances material on RLS algorithms; strengthens linkages to Kalman filter theory to gain a more unified treatment of the standard, square-root and order-recursive forms; and includes new computer experiments using MATLAB software that illustrate the underlying theory and applications of the LMS and RLS algorithms.
Book Synopsis Novel Adaptive Optics Concepts by : Stephan Kellner
Download or read book Novel Adaptive Optics Concepts written by Stephan Kellner and published by . This book was released on 2005 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Linear and Non-Linear Preprocessing of Wavefront Sensor Slope Measurements for Improved Adaptive Optics Performance by : Dennis Anthony Montera
Download or read book Linear and Non-Linear Preprocessing of Wavefront Sensor Slope Measurements for Improved Adaptive Optics Performance written by Dennis Anthony Montera and published by . This book was released on 1996-03-01 with total page 104 pages. Available in PDF, EPUB and Kindle. Book excerpt: New methods for preprocessing wavefront sensor (WFS) slope measurements are presented. Methods are developed to improve the accuracy of WFS slope measurements, as well as estimating key atmospheric and system parameters from the slope signals. Both statistical and artificial neural network solutions are investigated. Also, new atmospheric models for generating slope and phase data with the proper spatial and temporal statistics are developed. The experiments in improving the accuracy of WFS slope measurements include reducing the WFS slope measurement error and compensating for adaptive optics system time delay through temporal slope prediction. The experiments in key parameter estimation include estimating the Fried coherence length, r0, the wind speed profile, the strengths of the atmospheric turbulence layers, and the WFS mean square slope estimation error. Results of the experiments are used to make generalized conclusions in several key areas: first, the types of useful information that can be extracted from the WFS slope measurements; second, a comparison of linear or non linear methods; and third, the possibility of methods that can be developed which operate over useful ranges of seeing conditions. Overall, we find that the WFS slope measurements do contain useful information which can be extracted through various techniques. Simple transformations (either by neural network or statistical solution) on slope measurements can yield significant improvements is system accuracy without major changes to the adaptive optics system.
Book Synopsis Big Data in Astronomy by : Linghe Kong
Download or read book Big Data in Astronomy written by Linghe Kong and published by Elsevier. This book was released on 2020-06-13 with total page 440 pages. Available in PDF, EPUB and Kindle. Book excerpt: Big Data in Radio Astronomy: Scientific Data Processing for Advanced Radio Telescopes provides the latest research developments in big data methods and techniques for radio astronomy. Providing examples from such projects as the Square Kilometer Array (SKA), the world’s largest radio telescope that generates over an Exabyte of data every day, the book offers solutions for coping with the challenges and opportunities presented by the exponential growth of astronomical data. Presenting state-of-the-art results and research, this book is a timely reference for both practitioners and researchers working in radio astronomy, as well as students looking for a basic understanding of big data in astronomy. Bridges the gap between radio astronomy and computer science Includes coverage of the observation lifecycle as well as data collection, processing and analysis Presents state-of-the-art research and techniques in big data related to radio astronomy Utilizes real-world examples, such as Square Kilometer Array (SKA) and Five-hundred-meter Aperture Spherical radio Telescope (FAST)
Book Synopsis Optics in Atmospheric Propagation and Adaptive Systems by :
Download or read book Optics in Atmospheric Propagation and Adaptive Systems written by and published by . This book was released on 2002 with total page 242 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis A Question and Answer Guide to Astronomy by : Pierre-Yves Bely
Download or read book A Question and Answer Guide to Astronomy written by Pierre-Yves Bely and published by Cambridge University Press. This book was released on 2017-03-23 with total page 361 pages. Available in PDF, EPUB and Kindle. Book excerpt: Contains 250 questions and answers about astronomy, particular for the amateur astronomer.
Download or read book The Solar Optical Telescope written by and published by . This book was released on 1984 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Solar Observations written by F. Sánchez and published by Cambridge University Press. This book was released on 1992 with total page 274 pages. Available in PDF, EPUB and Kindle. Book excerpt: First Canary Islands Winter School Workshop in which four internationally respected scientists write on solar physics.
