Download or read book A Practical Comparison of Phase Diversity to Interferometry in Measuring the Aberrations in an Adaptive Optics System written by and published by . This book was released on 1999 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Any adaptive optics system must be calibrated with respect to internal aberrations in order for it to properly correct the starlight before it enters the science camera. Typical internal calibration consists of using a point source stimulus at the input to the AO system and recording the wavefront at the output. Two methods for such calibration have been implemented on the adaptive optics system at Lick Observatory. The first technique, Phase Diversity, consists of taking out of focus images with the science camera and using an iterative algorithm to estimate the system wavefront. A second technique uses a newly installed instrument, the Phase-Shifting Diffraction Interferometer, which has the promise of providing very high accuracy wavefront measurements. During observing campaigns in 1998, both of these methods were used for initial calibrations. In this paper we present results and compare the two methods in regard to accuracy and their practical aspects.
Download or read book Adaptive Optics written by Michael S. Tarov and published by Nova Publishers. This book was released on 2002 with total page 136 pages. Available in PDF, EPUB and Kindle. Book excerpt: Adaptive optics is a field which is coming into its own with new discoveries occurring almost daily both in astronomy and in applications of AO in applied fields. In an adaptive optics system, the output from a wavefront sensor is used to calculate corrections that actively remove distortions from an image. The applications of adaptive optics in vision science have received considerable impetus from the knowledge developed by astronomers about how to correct images using AO technology. It is expected that developments in adaptive optics will radically change the face of astronomy in the 21st century. These systems will largely overcome the main limitation of ground-based telescopes, namely the severe reduction in image quality caused by turbulence in the Earth's atmosphere. Intended for use at near infrared wavelengths, adaptive optics allow imaging and spectroscopy at the limit of resolution imposed by optical diffraction an advance in astronomer's ability to view the heavens unparalleled since the invention of the telescope. AO is now also entering clinical medicine in the field of ophthalmology and other related fields. This new book presents several hundred current abstracts in the field, each fully indexed, for ease of access and contains a CD ROM for further research.
Download or read book International Aerospace Abstracts written by and published by . This book was released on 1999 with total page 974 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Proceedings of the 3rd International Conference on Multimedia Technology ICMT 2013 written by Aly A. Farag and published by Springer Science & Business Media. This book was released on 2013-11-19 with total page 406 pages. Available in PDF, EPUB and Kindle. Book excerpt: Proceedings of the 3rd International Conference on Multimedia Technology (ICMT2013) focuses on both the theory and applications of multimedia technology. The recent advances, new research findings and applications in the fields of theoretical, experimental and applied image & video processing and multimedia technology presented at the conference are brought together in this book. It will serve as a valuable reference for scientists and engineers working in multimedia and related fields. Prof. Aly A. Farag works at the University of Louisville, USA; Prof. Jian Yang works at Tsinghua University, China; Dr. Feng Jiao works at Nanjing University of Information Science & Technology, China.
Download or read book Adaptive Optics Systems Based on Feedback Interferometry written by Dexter Chi Lun Cheung and published by . This book was released on 2005 with total page 242 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Detection and Characterization of Low Mass Companions to Sun Like Stars written by James Patrick Lloyd and published by . This book was released on 2002 with total page 560 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book High accuracy Calibration of an Adaptive Optics System Using a Phase Shifting Diffraction Interferometer written by and published by . This book was released on 1999 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A phase-shifting diffraction interferometer (PSDI) has been integrated into an adaptive optics (AO) system developed by LLNL for use on the three meter Shane telescope at Lick Observatory. The interferometer is an all fiber optic design, which is extremely compact. It is useful for calibrating the control sensors, measuring the aberrations of the entire AO optical train, and measuring the influence functions of the individual actuators on the deformable mirror. The PSDI is particularly well suited for this application because it measures converging, quasi-spherical wavefronts, such as are produced by an AO imaging system. Thus, a PSDI can be used to measure the aberrations of the entire AO system, in-situ and without errors introduced by auxiliary optics. This provides an extremely accurate measurement ((approximately) 5 nm RMS) of the optical properties of the AO system.
Download or read book Optical and IR Telescope Instrumentation and Detectors written by and published by . This book was released on 2000 with total page 756 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Phase Estimation in Optical Interferometry written by Pramod Rastogi and published by CRC Press. This book was released on 2014-11-21 with total page 364 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book covers the essentials of phase-stepping algorithms used in interferometry and pseudointerferometric techniques. It presents the basic concepts and mathematics needed for understanding modern phase estimation methods. The book first focuses on phase retrieval from image transforms using a single frame. It then examines the local environment of a fringe pattern, the phase estimation approach based on local polynomial phase modeling, temporal high-resolution phase evaluation methods, and methods of phase unwrapping. It also discusses experimental imperfections liable to adversely influence the accuracy of phase measurements.
Download or read book Catching the Perfect Wave written by Sergio R. Restaino and published by . This book was released on 1999 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Principles of Adaptive Optics written by Robert K. Tyson and published by CRC Press. This book was released on 2022-02-28 with total page 356 pages. Available in PDF, EPUB and Kindle. Book excerpt: Principles of Adaptive Optics describes the foundations, principles, and applications of adaptive optics (AO) and its enabling technologies. This leading textbook addresses the fundamentals of AO at the core of astronomy, high-energy lasers, biomedical imaging, and optical communications. Key Features: Numerous examples to explain and support the underlying principles Hundreds of new references to support the topics that are addressed End-of-chapter questions and exercises A complete system design example threaded through each chapter as new material is introduced
Download or read book Adaptive Optics and Phase Diversity Imaging for Responsive Space Applications written by Mark William Smith and published by . This book was released on 2004 with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt: The combination of phase diversity and adaptive optics offers great flexibility. Phase diverse images can be used to diagnose aberrations and then provide feedback control to the optics to correct the aberrations. Alternatively, phase diversity can be used to partially compensate for aberrations during post-detection image processing. The adaptive optic can produce simple defocus or more complex types of phase diversity. This report presents an analysis, based on numerical simulations, of the efficiency of different modes of phase diversity with respect to compensating for specific aberrations during post-processing. It also comments on the efficiency of post-processing versus direct aberration correction. The construction of a bench top optical system that uses a membrane mirror as an active optic is described. The results of characterization tests performed on the bench top optical system are presented. The work described in this report was conducted to explore the use of adaptive optics and phase diversity imaging for responsive space applications.
Download or read book Phase Diversity Wavefront Sensing for Control of Space Based Adaptive Optics Systems written by and published by . This book was released on 2007 with total page 55 pages. Available in PDF, EPUB and Kindle. Book excerpt: Phase Diversity Wavefront Sensing (PD WFS) is a wavefront reconstruction technique used in adaptive optics, which takes advantage of the curvature conjugating analog physical properties of a deformable mirror (MMDM or Bi-morph) such that the computational intensity required for correcting an aberrated wavefront, becomes simplified over traditional Shack-Hartmann WFS techniques. By looking at an image reflected off a deformable mirror by two cameras placed on either side of focus of a lens, intensity differences, indicating wavefront aberration in the beam, can be detected by the cameras acting together as a WFS and analyzed by a computer providing control to the actuators of a deformable mirror such that any detected difference in intensities between the two cameras can be minimized. This process of mirror surface conjugation serves to correct for the aberrated or curved wavefront by reflecting a new wavefront, compensated for curvature, such that its reflection is approximately planar. The theory of PD WFS is well documented however, there is very little quantifiable information regarding the specific challenges in designing a functioning PD WFS. In this research a PD WFS was designed and the concept proven such that a wavefront could be corrected through a computer controlled closed loop conjugation of a deformable mirror. The results were analyzed using a traditional Shack-Hartmann WFS and off-the-shelf "Front Surfer" wavefront analysis software to verify the validity of the experimental data. PD WFS has become critical in the development of segmented mirror adaptive optical systems where traditional wavefront reconstruction using Shack-Hartmann wavefront sensing tends to break down at the mirror segment edges. The Naval Postgraduate School, Spacecraft Research and Design Center (SRDC) intends to explore the use of a segmented mirror adaptive optical systems for space based applications.
Download or read book Fringe Pattern Analysis for Optical Metrology written by Manuel Servin and published by John Wiley & Sons. This book was released on 2014-05-30 with total page 344 pages. Available in PDF, EPUB and Kindle. Book excerpt: The main objective of this book is to present the basic theoretical principles and practical applications for the classical interferometric techniques and the most advanced methods in the field of modern fringe pattern analysis applied to optical metrology. A major novelty of this work is the presentation of a unified theoretical framework based on the Fourier description of phase shifting interferometry using the Frequency Transfer Function (FTF) along with the theory of Stochastic Process for the straightforward analysis and synthesis of phase shifting algorithms with desired properties such as spectral response, detuning and signal-to-noise robustness, harmonic rejection, etc.
Download or read book Adaptive Aberration Correction Using Feedback Interferometry written by Geoffrey Terence Bold and published by . This book was released on 1996 with total page 276 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Adaptive Optics and Short Wavelength Sources written by Stephen F. Jacobs and published by Addison Wesley Publishing Company. This book was released on 1978 with total page 344 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book An Adaptive Optic for Correcting Low order Wavefront Aberrations written by and published by . This book was released on 1999 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Adaptive Optics used for correcting low-order wavefront aberrations were tested and compared using interferometry, beam propagation, and a far-field test. Results confirm that the design and manufacturing specifications were met. Experimental data also confirms theoretical performance expectations, indicating the usefulness of these optics (especially in a laser-beam processing system), and identifying the resulting differences between the two fabrication methods used to make the optics.
