Introduction to Geometric Optics

Introduction to Geometric Optics tài liệu, giáo án, bài giảng , luận văn, luận án, đồ án, bài tập lớn về tất cả các lĩnh...

CAMERAPhân tíchảnhNhận dạngThu nhận ảnhSố hoáHệ thốngThu nhận ảnhChương Một: NHẬP MÔN XỬ LÝ ẢNH NHẬP MÔN XỬ LÝ ẢNH INTRODUCTION TO DIGITAL IMAGE PROCESSING1.1 TỔNG QUAN VỀ MỘT HỆ THỐNG XỬ LÝ ẢNHXử lý ảnh là một khoa học còn tương đối mới mẻ so với nhiều ngành khoa học khác, nhất là trên qui mô công nghiệp, song trong xử lý ảnh đã bắt đầu xuất hiện những máy tính chuyên dụng. Để có thể hình dung cấu hình một hệ thống xử lý ảnh chuyên dụng hay một hệ thống xử lý ảnh dùng trong nghiên cứu, đào tạo, trước hết chúng ta sẽ xem xét các bước cần thiết trong xử lý ảnh.Trước hết là quá trình thu nhận ảnh. Ảnh có thể thu nhận qua camera. Thường ảnh thu nhận qua camera là tín hiệu tương tự (loại camera ống kiểu CCIR), nhưng cũng có thể là tín hiệu số hoá (loại CCD - Charge Coupled Device). Lưu trữ SENSOR Lưu trữ Hệ Q.Định Hình 1.1.a. Các giai đoạn chính trong xử lý ảnhẢnh cũng có thể thu nhận từ vệ tinh qua các bộ cảm ứng (sensor), hay ảnh, tranh được quét trên scanner. Chi tiết về quá trình thu nhận ảnh sẽ được mô tả trong chương 2. Tiếp theo là quá trình số hoá (Digitalizer) để biến đổi tín hiệu tương tự sang tín hiệu rời rạc (lấy mẫu) và số hoá bằng lượng hoá, trước khi chuyển sang giai đoạn xử lý, phân tích hay lưu trữ lại.Qúa trình phân tích ảnh thực chất bao gồm nhiều công đoạn nhỏ. Trước hết là công việc tăng cường ảnh để nâng cao chất lượng ảnh. Do những nguyên nhân khác nhau: có thể do chất lượng thiết bị thu nhận ảnh, do nguồn sáng hay do nhiễu, ảnh có thể bị suy biến. Do vậy cần phải tăng cường và khôi phục lại ảnh để làm nổi bật một số đặc tính chính của ảnh, hay làm cho ảnh gần giống nhất với trạng thái gốc- trạng thái trước khi ảnh bị biến dạng. Giai đoạn tiếp theo là phát hiện các đặc tính như biên, phân vùng ảnh, trích chọn các đặc tính, v.v .Nhập môn xử lý ảnh số - ĐHBK Hà nội 11 Chương Một: NHẬP MÔN XỬ LÝ ẢNH Cuối cùng, tuỳ theo mục đích của ứng dụng, sẽ là giai đoạn nhận dạng, phân lớp hay các quyết định khác. Các giai đoạn chính của quá trình xử lý ảnh có thể mô tả ở hình 1.1.a.Với các giai đoạn trên, một hệ thống xử lý ảnh (cấu trúc phần cứng theo chức năng) gồm các thành phần tối thiểu như hình 1.1.b. Đối với một hệ thống xử lý ảnh thu nhận qua camera-camera như là con mắt của hệ thống. Có 2 loại camera: camera ống loại CCIR và camera CCD. Loại camera ứng với chuẩn CCIR quét ảnh với tần số 1/25 và mỗi ảnh gồm 625 dòng. Loại CCD gồm các photo điốt và làm tương ứng một cường độ sáng tại một điểm ảnh ứng với một phần tử ảnh (pixel). Như vậy, ảnh là tập hợp các điểm ảnh. Số pixel tạo nên một ảnh gọi là độ phân giải (resolution). Bộ xử lý tương tự (analog processor). Bộ phận này thực hiện các chức năng sau:- Chọn camera thích hợp nếu hệ thống có nhiều camera.- Chọn màn hình hiển thị tín hiệu- Thu nhận tín hiệu video thu nhận bởi bộ số hoá(digitalizer). Thực hiện lấy mẫu và mã hoá.- Tiền xử lý Introduction to Geometric Optics Introduction to Geometric Optics Bởi: OpenStaxCollege Geometric Optics Light from this page or screen is formed into an image by the lens of your eye, much as the lens of the camera that made this photograph Mirrors, like lenses, can also form images that in turn are captured by your eye 1/3 Introduction to Geometric Optics Image seen as a result of reflection of light on a plane smooth surface (credit: NASA Goddard Photo and Video, via Flickr) Our lives are filled with light Through vision, the most valued of our senses, light can evoke spiritual emotions, such as when we view a magnificent sunset or glimpse a rainbow breaking through the clouds Light can also simply amuse us in a theater, or warn us to stop at an intersection It has innumerable uses beyond vision Light can carry telephone signals through glass fibers or cook a meal in a solar oven Life itself could not exist without light’s energy From photosynthesis in plants to the sun warming a cold-blooded animal, its supply of energy is vital 2/3 Introduction to Geometric Optics Double Rainbow over the bay of Pocitos in Montevideo, Uruguay (credit: Madrax, Wikimedia Commons) We already know that visible light is the type of electromagnetic waves to which our eyes respond That knowledge still leaves many questions regarding the nature of light and vision What is color, and how our eyes detect it? Why diamonds sparkle? How does light travel? How lenses and mirrors form images? These are but a few of the questions that are answered by the study of optics Optics is the branch of physics that deals with the behavior of visible light and other electromagnetic waves In particular, optics is concerned with the generation and propagation of light and its interaction with matter What we have already learned about the generation of light in our study of heat transfer by radiation will be expanded upon in later topics, especially those on atomic physics Now, we will concentrate on the propagation of light and its interaction with matter It is convenient to divide optics into two major parts based on the size of objects that light encounters When light interacts with an object that is several times as large as the light’s wavelength, its observable behavior is like that of a ray; it does not prominently display its wave characteristics We call this part of optics “geometric optics.” This chapter will concentrate on such situations When light interacts with smaller objects, it has very prominent wave characteristics, such as constructive and destructive interference Wave Optics will concentrate on such situations 3/3 An introduction to disk drivemodelingChris Ruemmler and John WilkesHewlett-Packard Laboratories, Palo Alto, CAMuch research in I/O systems is based on disk drive simulation models, but howgood are they? An accurate simulation model should emphasize the performance-critical areas.This paper has been published in IEEE Computer 27(3):17–29, March 1994. Itsupersedes HP Labs technical reports HPL–93–68 rev 1 and HPL–OSR–93–29.Copyright © 1994 IEEE.Internal or personal use of this material is permitted. However, permission toreprint/republish this material for advertising or promotional purposes or forcreating new collective works for resale or redistribution must be obtained from theIEEE. To receive more information on obtaining permission, send a blank emailmessage to info.pub.permission@ieee.org.Note: this file was obtained by scanning and performing OCR on the IEEEpublished copy. As a result, it may contain typographic or other errors that are notin the published version. Minor clarifications and updates have been made to thebibliography. 1Modern microprocessor technology is advancing at an incredible rate, and speedups of 40 to 60 percentcompounded annually have become the norm. Although disk storage densities are also improvingimpressively (60 to 80 percent compounded annually), performance improvements have been occurring atonly about 7 to 10 percent compounded annually over the last decade. As a result, disk system performanceis fast becoming a dominant factor in overall system behavior.Naturally, researchers want to improve overall I/O performance, of which a large component is theperformance of the disk drive itself. This research often involves using analytical or simulation models tocompare alternative approaches, and the quality of these models determines the quality of the conclusions;indeed, the wrong modeling assumptions can lead to erroneous conclusions. Nevertheless, little work hasbeen done to develop or describe accurate disk drive models. This may explain the commonplace use ofsimple, relatively inaccurate models.We believe there is much room for improvement. This article demonstrates and describes a calibrated, high-quality disk drive model in which the overall error factor is 14 times smaller than that of a simple first-ordermodel. We describe the various disk drive performance components separately, then show how theirinclusion improves the simulation model. This enables an informed trade-off between effort and accuracy.In addition, we provide detailed characteristics for two disk drives, as well as a brief description of asimulation environment that uses the disk drive model.Characteristics of modern disk drivesTo model disk drives, we must understand how they behave. Thus, we begin with an overview of the currentstate of the art in nonremovable magnetic disk drives with embedded SCSI (Small Computer SystemsInterconnect) controllers, since these are widely available.Disk drives contain a mechanism and a controller. The mechanism is made up of the recording components(the rotating disks and the heads that access them) and the positioning components (an arm assembly thatmoves the heads into the correct position together with a track-following system that keeps it in place). Thedisk controller contains a microprocessor, some buffer memory, and an interface to the SCSI bus. Thecontroller manages the storage and retrieval of data to and from the mechanism and performs mappingsbetween incoming logical addresses and the physical disk sectors that store the information.Below, we look more closely at each of these elements, emphasizing features that need to be consideredwhen creating a disk drive model. It will become clear Introduction to Fourier Optics McGraw-Hill Series in Electrical and Computer Engineering SENIOR CONSULTING EDITOR Stephen W. Director, Carnegie Mellon University Circuits and Systems Communications and Signal Processing Computer Engineering Control Theory Electromagnetics Electronics and VLSI Circuits Introductory Power and Energy Radar and Antennas PREVIOUS CONSULTING EDITORS Ronald N. Bracewell, Colin Cherry, James F. Gibbons, Willis W. Harman, Hubert Heffner, Edward W. Herold, John G. Linvill, Simon Ramo, Ronald A. Rohrer, Anthony E. Siegman, Charles Susskind, Frederick E. Terman, John G. Truxal, Ernst Weber, and John R. Whinnery Elec tromagnetics SENIOR CONSULTING EDITOR Stephen W. Director, Carnegie Mellon University Dearhold and McSpadden: Electromagnetic Wave Propagation Goodman: Introduction to Fourier Optics Harrington: Time - Harmonic Electromagnetic Fields Hayt: Engineering Electromagnetics Kraus: Electromagnetics Paul and Nasar: Introduction to Electromagnetic Fields Plonus: Applied Electromagnetics Introduction to Fourier Optics SECOND EDITION Joseph W. Goodman Stanford University THE McGRAW-HILL COMPANIES, INC. New York St. Louis San Francisco Auckland Bogot6 Caracas Lisbon London Madrid Mexico City Milan Montreal New Delhi San Juan Singapore Sydney Tokyo Toronto [...]... angle 8 (with respect to the x axis) given by In addition, the spatial period (i.e the distance between zero-phase lines) is given by 8 Introduction to Fourier Optics \ \ FIGURE 2.1 - - - - - Lines of zero phase for the fur exp[j2.rr(fxn + fry)] - In conclusion, then, we may again regard the inverse Fourier transform as providing a means for decomposing mathematical functions The Fourier spectrum G of... of Photographic Emulsions 7.2 Spatial Light Modulators 7.2.1 Properties of Liquid Crystals / 7.2.2 Spatial Light Modulators Based on Liquid Crystals / 7.2.3 Magneto-Optic Spatial Light Modulators / 7.2.4 Deformable Mirror Spatial Light Modulators / 7.2.5 Multiple Quantum Well Spatial Light Modulators / 7.2.6 Acousto-Optic Spatial Light Modulators 7.3 Diffractive Optical Elements 7.3.1 Binary Optics. .. decomposition are, of course, just these 6 functions To find the response of the system to the input gl, substitute ( 2-4 3) in ( 2-4 1): Now, regarding the number gl(5, q ) as simply a weighting factor applied to the elementary function 6(x1 - 5, yl - q), the linearity property ( 2-4 2) is invoked to allow S { )to operate on the individual elementary functions; thus the operator S{} brought is within the integral, yielding... functions separable in rectangular coordinates Function e x - ( a +2 2 Transform ?- exp y 2 lab1 [ (2+ 2 )] -n - - I 6(ax,by) - exp[j.rr(ax+ by)] sgn(ax) sgn(by) ab 1 - 1 comb(ax) comb(by) -comb(fxla) comb(fylb) exp[jn(a 2 x 2+ b2y2)] - exp [-( alxl + blyl)l Circle function lab1 6(fx - al2, f~ - bl2) 1 lab1 1 circ( ) / , lab1 jnfx jnfy 1 lab1 2 / , = 2 + ( 2 nf ~ l a )1 ~ (27rfylb)2 + = 1 ( 0 otherwise... also like to thank the students in my 1995 Fourier Optics class, who competed fiercely to see who could find the most mistakes Undoubtedly there are others to whom I owe thanks, and I apologize for not mentioning them explicitly here Finally, I thank Hon Mai, without whose patience, encouragement and support this book would not have have been possible Joseph W Goodm[...]... 3-D Optical Storage 8.4.6 Photochemical Hole-Burning 3-D Storage 8.5 Holographic Optical Storage 8.5.1 Principle of Holography 8.5.2 Plane Holographic Storage 8.5.3 Stacked Holograms for 3-D Optical Storage 8.5.4 Volume Holographic 3-D Optical Storage 8.6 Near Field Optical Storage 8.7 Concluding Remarks References Exercises Chapter 9 9.1 9.2 9.3 9.4 9.5 9.6 9.7 Computing with Optics Introduction Parallel... application of which can range from very abstract artistic interpretations to very efficient scientific usages This chapter discusses the relationship between entropy information and optics Our intention is not to provide a detailed discussion, however, but to cover the basic fundamentals that are easily applied to optics We note that entropy information was not originated by optical scientists, but rather by... entropy information, interest in its application has never totally been absent from the optical standpoint As a result of the recent development of optical communication, signal processing, and computing, among other discoveries, the relationship between optics and entropy information has grown more profound than ever 2 1 Entropy Information and Optics 1.1 INFORMATION TRANSMISSION Although we seem to know... (1.28) where H(A/B) represents the amount of information loss (e.g., due to noise) or the equivocation of the channel, which is the average amount of information needed to specify the noise disturbance in the channel And H(B/A) is referred to as the noise entropy of the channel To conclude this section, we note that the entropy information can be easily extended to continuous product space, such as p(a)log2p(a)da,... Sensors 10.4 Summary References Exercises 589 589 600 612 613 615 Chapter 11 617 Information Display with Optics 11.1 I ntrod action 11.2 Information Display Using Acousto-optic Spatial Light Modulators 11.2.1 The Acousto-optic Effect 11.2.2 Intensity Modulation of Laser 11.2.3 Deflection of Laser 11.2.4 Laser TV Display Using Acousto-optic Devices 11.3 3-D Holographic Display 11.3.1 Principles of Holography... not only the source of energy necessary to live — plants grow up by drawing energy from sunlight; light is also the source of energy for information - our vision is based on light detected by our eyes (but we do not grow up by drawing energy from light to our body through our eyes) Furthermore, applications of optics to information technology are not limited to vision and can be found almost everywhere... interests in optical applications to information technology In view of the great number of contributions in this area, we have not been able to include all of them in this book Chapter 1 Entropy Information and Optics Francis T.S Yu THE PENNSYLVANIA STATE UNIVERSITY Light is not only the mainstream of energy that supports life; it also provides us with an important source of information One can easily imagine... therefore able to advance themselves above the rest of the animals on this planet Earth It is undoubtedly true that if humans did not have eyes, they would not have evolved into their present form In the presence of Introduction to Fiber Optics Prelims 3/5/01 11:48 Page i Prelims 3/5/01 11:48 Page ii Introduction to Fiber Optics 2nd Edition John Crisp OXFORD AUCKLAND BOSTON JOHANNESBURG MELBOURNE NEW DELHI Prelims 3/5/01 11:48 Page iii Newnes An imprint of Butterworth–Heinemann Linacre House, Jordan Hill, Oxford OX2 8DP A division of Reed Educational and Professional Publishing Ltd A member of the Reed Elsevier plc group First published 1996 Reprinted 1997, 1998, 1999, 2000 (three times), 2001 Second edition 2001 © John Crisp 1996, 2001 All rights reserved. No part of this publication may be reproduced in any material form (including photocopying or storing in any medium by electronic means and whether or not transiently or incidentally to some other use of this publication) without the written permission of the copyright holder except in accordance with the provisions of the Copyright, Designs and Patents Act 1988 or under the terms of a licence issued by the Copyright Licensing Agency Ltd, 90 Tottenham Court Road, London, England W1P 0LP. Applications for the copyright holder’s written permission to reproduce any part of this publication should be addressed to the publishers. British Library Cataloguing in Publication Data A catalogue record for this book is available from the British Library ISBN 07506 50303 Composition by Scribe Design, Gillingham, Kent Printed and bound in Great Britain by Biddles Ltd, www.biddles.co.uk Prelims 3/5/01 11:48 Page iv Preface vii 1 Optic fiber and light — a brilliant combination 1 2 What makes the light stay in the fiber? 9 3 The choice of frequency 17 4 Propagation of light along the fiber 22 5 Decibels 39 6 Losses in optic fibers 50 7 Dispersion and our attempts to prevent it 59 8 Real cables 68 9 Connecting optic fibers — the problems 82 10 Fusion splicing 92 11 Mechanical splices 103 12 Connectors 108 13 Couplers 126 14 Light sources and detectors 139 15 Testing a system 147 16 System design — or, will it work? 166 17 The transmission of signals 183 18 Organizing optic fiber within a building 192 19 LANs and topology 200 Contents Prelims 3/5/01 11:48 Page v 20 Some final thoughts 206 Glossary 210 Quiz time answers 217 Index 227 Contents vi Prelims 3/5/01 11:48 Page vi An increasing proportion of the world’s communications are carried by fiber optic cables. It has spread quietly, almost without being noticed into every situa- tion in which information is being transmitted whether it is within the home hi-fi system, cable television or telecommunication cables under the oceans. The purpose of this book is to provide a worry-free introduction to the subject. It starts at the beginning and does not assume any previous knowledge of the subject and, in gentle steps, it introduces the theory and practical knowledge that is necessary to use and understand this new technology. In learning any new subject jargon is a real problem. When the words are understood by all parties they make an efficient shorthand form of communi- cation. Herein lies the snag. If not understood, jargon can create an almost impenetrable barrier to keep us out. In this book jargon is introduced only when required and in easily digested snacks. John Crisp Preface Prelims 3/5/01 11:48 Page vii Prelims 3/5/01 11:48 Page viii The starting point For thousands of years we have used light to communicate. The welcoming camp fire guided us home and kept wild animals at bay. Signal bonfires were lit on hilltops to warn of invasion. Even in these high-tech days of satellite communications, ships still carry powerful lamps for signaling at sea, signaling mirrors are standard issue in survival packs. It was a well known ‘fact’ that, as light travels in straight lines, it is impossible to make it follow a curved path to shine around corners. Boston, Mass., USA, 1870. An Irish ... energy From photosynthesis in plants to the sun warming a cold-blooded animal, its supply of energy is vital 2/3 Introduction to Geometric Optics Double Rainbow over the bay of Pocitos in Montevideo,.. .Introduction to Geometric Optics Image seen as a result of reflection of light on a plane smooth surface (credit: NASA Goddard Photo and Video, via Flickr) Our lives... upon in later topics, especially those on atomic physics Now, we will concentrate on the propagation of light and its interaction with matter It is convenient to divide optics into two major parts