Distributed Control of a Retinal Imaging Adaptive Optics System
Distributed Control of a Retinal Imaging Adaptive Optics System

Author: Maurizio Ficocelli

Publisher:

Published: 2008

Total Pages: 500

ISBN-13: 9780494447802

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In recent years a technique known as adaptive optics (AO), commonly used to correct the dynamic wavefront error caused by atmospheric turbulence in ground-based telescopes, has been studied as a means of correcting the dynamic wavefront error caused by aberrations in the human eye, allowing for higher resolution retinal images. In order to compensate for these dynamic aberrations, a compact AO system that tracks and compensates for these changes in real-time is needed. To realize such a system, improvements must be made in two key components, namely the control algorithms and the design of the wavefront corrector. The latter represents the main focus of this thesis. The control problem in adaptive optics systems is generalized to that of shape control for a flexible membrane representing a deformable membrane mirror used in the wavefront corrector. Due to the dynamic nature of the aberrations in the eye, the shape control problem addressed is the tracking of an unknown and time-varying shape for a distributed membrane (i.e., desired shape of the mirror). The proposed controller design approach relies on two steps. The first step is to construct a Q -parameterized set of stabilizing controllers for the system under consideration and to derive conditions on the Q parameter in the controller expression to achieve regulation. Since the desired shape of the mirror is unknown and time-varying, the second step is to derive an online tuning algorithm for the Q parameter in the expression for the parameterized stabilizing controller. The online tuning of the Q parameter allows the controller to converge to the controller needed to achieve regulation, hence compensating for the lack of information on the desired shape for the deformable mirror. Decoupling introduced in the closed loop system allows tuning to be performed using decentralized algorithms.

Adaptive Optics Progress
Adaptive Optics Progress

Author: Robert Tyson

Publisher: BoD – Books on Demand

Published: 2012-12-18

Total Pages: 232

ISBN-13: 9535108948

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For over four decades there has been continuous progress in adaptive optics technology, theory, and systems development. Recently there also has been an explosion of applications of adaptive optics throughout the fields of communications and medicine in addition to its original uses in astronomy and beam propagation. This volume is a compilation of research and tutorials from a variety of international authors with expertise in theory, engineering, and technology. Eight chapters include discussion of retinal imaging, solar astronomy, wavefront-sensorless adaptive optics systems, liquid crystal wavefront correctors, membrane deformable mirrors, digital adaptive optics, optical vortices, and coupled anisoplanatism.

High Resolution Imaging in Microscopy and Ophthalmology
High Resolution Imaging in Microscopy and Ophthalmology

Author: Josef F. Bille

Publisher: Springer

Published: 2019-08-13

Total Pages: 407

ISBN-13: 3030166384

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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.

Modeling and Control of Magnetic Fluid Deformable Mirrors for Adaptive Optics Systems
Modeling and Control of Magnetic Fluid Deformable Mirrors for Adaptive Optics Systems

Author: Zhizheng Wu

Publisher: Springer Science & Business Media

Published: 2012-10-21

Total Pages: 323

ISBN-13: 364232228X

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Modeling and Control of Magnetic Fluid Deformable Mirrors for Adaptive Optics Systems presents a novel design of wavefront correctors based on magnetic fluid deformable mirrors (MFDM) as well as corresponding control algorithms. The presented wavefront correctors are characterized by their linear, dynamic response. Various mirror surface shape control algorithms are presented along with experimental evaluations of the performance of the resulting adaptive optics systems. Adaptive optics (AO) systems are used in various fields of application to enhance the performance of optical systems, such as imaging, laser, free space optical communication systems, etc. This book is intended for undergraduate and graduate students, professors, engineers, scientists and researchers working on the design of adaptive optics systems and their various emerging fields of application. Zhizheng Wu is an associate professor at Shanghai University, China. Azhar Iqbal is a research associate at the University of Toronto, Canada. Foued Ben Amara is an assistant professor at the University of Toronto, Canada.

Principles Of Adaptive Optics
Principles Of Adaptive Optics

Author: Robert Tyson

Publisher: Academic Press

Published: 2012-12-02

Total Pages: 311

ISBN-13: 0323156592

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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.

Adaptive Optics for Industry and Medicine
Adaptive Optics for Industry and Medicine

Author: Christopher Dainty

Publisher: Imperial College Press

Published: 2008

Total Pages: 519

ISBN-13: 1848161115

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This proceedings volume presents the very latest developments in non-astronomical adaptive optics. This international workshop, the sixth in a biennial series, was the largest ever held and boasted significant involvement by industry. Adaptive optics is on the verge of being used in many products; indeed, at this meeting, the use of adaptive optics in DVD players was disclosed for the first time. Sample Chapter(s). Liquid Crystal Lenses For Correction Of Presbyopia (586 KB). Contents: Wavefront Correctors and Control: Liquid Crystal Lenses for Correction of Presbyopia (G Li & N Peyghambarian); Woofer-Tweeter Adaptive Optics (T Farrell & C Dainty); Wavefront Sensors: A Fundamental Limit for Wavefront Sensing (C Paterson); Direct Diffractive Image Simulation (A P Maryasov et al.); Adaptive Optics in Vision Science: A Study of Field Aberrations in the Human Eye (A V Goncharov et al.); Characterization of an AO-OCT System (J W Evans et al.); Adaptive Optics in Optical Storage and Microscopy: Commercialization of the Adaptive Scanning Optical Microscope (ASOM) (B Potsaid et al.); Towards Four Dimensional Particle Tracking for Biological Applications (H I Campbell et al.); Adaptive Optics in Lasers: New Results in High Power Lasers Beam Correction (A Kudryashov et al.); Adaptive Optics Control of Solid-State Lasers (W Lubeigt et al.); Adaptive Optics in Communication and Atmospheric Compensation: Fourier Image Sharpness Sensor for Laser Communications (K N Walker & R K Tyson); Adaptive Optics System for a Small Telescope (G Vdovin et al.); and other papers. Readership: Industry- and university-level researchers in optics and laser physics.