Download or read book Optimal Maneuvers for Distributed Aperture Imaging Systems written by Danielle Marie Fitch and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Interest in space-borne, distributed multi-aperture interferometric systems is driven by a need for continuously sustained imaging with high resolution. Amplitude interferometry systems measure the Fourier components of the image corresponding to the wave vectors (locations in the so-called u-v plane) that are proportional to the relative positions of the apertures. Imaging to specified resolution demands measurement of the Fourier components with adequate signal-to-noise ratio over the interior of a disk in the u-v plane (the resolution disk). In this paper we concentrate on the case in which interferometric measurements are made while the apertures are changing their relative positions. This work discusses heuristic maneuvers and strategies for a system of two space-borne telescopes to cover the frequency plane while optimizing a cost function that includes both a measure of image quality and propulsive effort. The current study is motivated by previous research in which the optimization problem was formulated and the first-order necessary conditions (FONC) derived. The earlier work obtained short time horizon solutions to the FONC for various simple situations, but the complexity of the integro-differential equations for optimal maneuvering have heretofore prevented solution for an optimal maneuver for the entirety of the imaging process. In place of a direct attack on the FONC, the present work investigates various heuristic approaches to minimizing the cost function in the discretized state and discretized time domains in a hexagonal coordinate system. Using three classes of coverage rules, experimentation with a variety of maneuver strategies involving two apertures has led to a number of time-optimal or fuel-optimal solutions based on the initial conditions of the spacecraft. This thesis shows that an optimal maneuver can be determined from the starting positions of the spacecraft and that a self-spiral class of motion seems to be the most beneficial for long term strategies. Future work may focus on strategies for interferometric systems with more than two apertures and with a finer mesh of the hexagonal coordinate system.
Download or read book Maneuvering of Distributed Space borne Sensors for Optimal Interferometric Imaging Performance written by Julie Sandberg and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The need for high resolution, continuously sustained imaging drives the interest in space-borne, distributed aperture, interferometric (amplitude, heterodyne, or intensity correlation) systems. This paper will discuss the maneuver controls for a system of multiple space-based telescopes to secure optimal image quality. Such distributed aperture systems eff ectively measure the Fourier Transform of the collected light so that the observed wave pattern is seen in the frequency plane. This Fourier Transform representation of physical spacecraft maneuvers may be interpreted as coverage regions (discs) in the frequency plane. Superior coverage of the frequency plane, which is directly related to image quality, is investigated for imaging distant objects using interferometric techniques where apertures are distributed on multiple space-based telescopes. The corresponding cost function is based on the optimality of the spacecraft maneuvers, which in turn is based on achieving a high image quality. This study builds on previous research wherein the first-order necessary conditions (FONC) were derived. The FONC are derived for specialized rectilinear motion and expanded to incorporate varying coverage disc velocities. These linearized equations are verifi ed to be consistent with those for the constant velocity case. Next, linearized first-order necessary conditions are shown to correspond closely with the fully nonlinear case. After that, the conditions for optimal overlap of the coverage paths will be given; these conditions lead to the optimal cost based on frequency plane parameters. Finally, a heuristic approach will be used to compare diff erent frequency plane coverage strategies. An analogy to painting will be presented to demonstrate adequate signal-to-noise ratio required for a desired image quality.
Download or read book Depth From Defocus A Real Aperture Imaging Approach written by Subhasis Chaudhuri and published by Springer Science & Business Media. This book was released on 1999-03-26 with total page 202 pages. Available in PDF, EPUB and Kindle. Book excerpt: Depth recovery is important in machine vision applications when a 3-dimensional structure must be derived from 2-dimensional images. This is an active area of research with applications ranging from industrial robotics to military imaging. This book provides the comprehensive details of the methodology, along with the complete mathematics and algorithms involved. Many new models, both deterministic and statistical, are introduced.
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 464 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Incoherent Multiple Aperture Optical Imaging Systems Analysis and Design written by Robert T. Reilander and published by . This book was released on 1987 with total page 131 pages. Available in PDF, EPUB and Kindle. Book excerpt: Various multiple aperture optical arrays were compared while imaging objects illuminated with incoherent light. The aperture arrays contained from one to four sub-apertures. The objects were edges, slits, rectangles and circles. An emphasis was placed on edge resolution, and the author derived his own set of resolution criteria. Based on this analysis, a tight square four-element array was the best performer. The study concluded with an analysis of design criteria for optimum incoherent imaging resolution. Max sub-aperture size, min sub-aperture spacing, max number of sub-aperture elements, and a symmetric pattern were all determined to be desirable in order to obtain the best performance.
Download or read book Advanced Guidance Navigation and Control for Remote Sensing written by Jesse Leitner and published by . This book was released on 1997 with total page 24 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Acoustical Imaging written by A.J. Berkhout and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 780 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Introduction to Subsurface Imaging written by Bahaa Saleh and published by Cambridge University Press. This book was released on 2011-03-17 with total page 455 pages. Available in PDF, EPUB and Kindle. Book excerpt: Describing and evaluating the basic principles and methods of subsurface sensing and imaging, Introduction to Subsurface Imaging is a clear and comprehensive treatment that links theory to a wide range of real-world applications in medicine, biology, security and geophysical/environmental exploration. It integrates the different sensing techniques (acoustic, electric, electromagnetic, optical, x-ray or particle beams) by unifying the underlying physical and mathematical similarities, and computational and algorithmic methods. Time-domain, spectral and multisensor methods are also covered, whilst all the necessary mathematical, statistical and linear systems tools are given in useful appendices to make the book self-contained. Featuring a logical blend of theory and applications, a wealth of color illustrations, homework problems and numerous case studies, this is suitable for use as both a course text and as a professional reference.
Download or read book Journal of the Indian Institute of Science written by Indian Institute of Science, Bangalore and published by . This book was released on 2006 with total page 882 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Spaceflight Mechanics written by and published by . This book was released on 2005 with total page 1150 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Applied Mechanics Reviews written by and published by . This book was released on 1982 with total page 916 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Space Station Systems written by and published by . This book was released on 1986 with total page 652 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Technology for Large Space Systems written by and published by . This book was released on 1989 with total page 676 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Large Space Structures Systems in the Space Station Era written by and published by . This book was released on 1991 with total page 336 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Dose Optimization in Digital Radiography and Computed Tomography written by Euclid Seeram and published by Springer Nature. This book was released on 2023-02-21 with total page 110 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book addresses radiation protection of patients having digital radiography and computed tomography (CT) examinations. The literature on radiation doses to patients from these two modalities have reported that the doses to patients are high. As a result, the radiology community has focused on methods and procedures to keep these doses as low as reasonably achievable (ALARA) without compromising the diagnostic image quality. This book outlines the motivation for dose optimization in radiology, identifies and describes the ICRP principle of optimization, outlines the factors affecting the dose in digital radiography and in CT, and identifies and describes strategies used in digital radiography and in CT for dose optimization. This book is intended for all those working in digital radiography and CT environments including radiological technologists, and radiographers, radiologists, biomedical engineering technologists, and student medical physicists. It is best used as a supplement to radiologic science textbooks, and in particular, radiation protection textbooks. Furthermore, this book lays the foundations for students and practitioners engaged in research on dose reduction and dose optimization in radiology. · Provides practical and useful methods for optimization of doses from digital radiography and CT · Describes the International Commission on Radiological Protection (ICRP) principle of optimization · Outlines the factors affecting the dose in digital radiography and in computed tomography
Download or read book Japanese Science and Technology 1983 1984 written by United States. National Aeronautics and Space Administration. Scientific and Technical Information Branch and published by . This book was released on 1985 with total page 1080 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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:
