Introduction to Functions

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 Functions Introduction to Functions By: OpenStaxCollege Standard and Poor’s Index with dividends reinvested (credit "bull": modification of work by Prayitno Hadinata; credit "graph": modification of work by MeasuringWorth) Toward the end of the twentieth century, the values of stocks of internet and technology companies rose dramatically As a result, the Standard and Poor’s stock market average rose as well [link] tracks the value of that initial investment of just under $100 over the 40 years It shows that an investment that was worth less than $500 until about 1995 skyrocketed up to about $1100 by the beginning of 2000 That five-year period became known as the “dot-com bubble” because so many internet startups were formed As bubbles tend to do, though, the dot-com bubble eventually burst Many companies grew too fast and then suddenly went out of business The result caused the sharp decline represented on the graph beginning at the end of 2000 Notice, as we consider this example, that there is a definite relationship between the year and stock market average For any year we choose, we can determine the corresponding value of the stock market average In this chapter, we will explore these kinds of relationships and their properties 1/1 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 Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-WesleyChapter 6I/O Streams as an Introduction to Objects and Classes Slide 6- 3Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-WesleyOverview6.1 Streams and Basic File I/O 6.2 Tools for Stream I/O6.3 Character I/O6.4 Inheritance Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley6.1Streams and Basic File I/O Slide 6- 5Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-WesleyI/O StreamsI/O refers to program input and outputInput is delivered to your program via a stream objectInput can be fromThe keyboardA fileOutput is delivered to the output device via a streamobjectOutput can be to The screenA file Slide 6- 6Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-WesleyObjectsObjects are special variables thatHave their own special-purpose functionsSet C++ apart from earlier programming languages Slide 6- 7Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-WesleyStreams and Basic File I/OFiles for I/O are the same type of files used tostore programsA stream is a flow of data.Input stream: Data flows into the programIf input stream flows from keyboard, the program willaccept data from the keyboardIf input stream flows from a file, the program will acceptdata from the fileOutput stream: Data flows out of the programTo the screenTo a file Slide 6- 8Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesleycin And cout StreamscinInput stream connected to the keyboardcout Output stream connected to the screencin and cout defined in the iostream libraryUse include directive: #include <iostream>You can declare your own streams to use with files. Slide 6- 9Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-WesleyWhy Use Files?Files allow you to store data permanently!Data output to a file lasts after the program endsAn input file can be used over and overNo typing of data again and again for testingCreate a data file or read an output file at yourconvenienceFiles allow you to deal with larger data sets Slide 6- 10Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-WesleyFile I/OReading from a fileTaking input from a fileDone from beginning to the end (for now)No backing up to read something again (OK to start over)Just as done from the keyboardWriting to a fileSending output to a fileDone from beginning to end (for now)No backing up to write something again( OK to start over)Just as done to the screen [...]... only to the stream named in the call Slide 6- 3 Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Overview 6.1 Streams and Basic File I/O 6.2 Tools for Stream I/O 6.3 Character I/O 6.4 Inheritance Slide 6- 45 Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Manipulators  A manipulator is a function called Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-WesleyChapter 6I/O Streams as an Introduction to Objects and Classes Slide 6- 3Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-WesleyOverview6.1 Streams and Basic File I/O 6.2 Tools for Stream I/O6.3 Character I/O6.4 Inheritance Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley6.1Streams and Basic File I/O Slide 6- 5Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-WesleyI/O StreamsI/O refers to program input and outputInput is delivered to your program via a stream objectInput can be fromThe keyboardA fileOutput is delivered to the output device via a streamobjectOutput can be to The screenA file Slide 6- 6Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-WesleyObjectsObjects are special variables thatHave their own special-purpose functionsSet C++ apart from earlier programming languages Slide 6- 7Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-WesleyStreams and Basic File I/OFiles for I/O are the same type of files used tostore programsA stream is a flow of data.Input stream: Data flows into the programIf input stream flows from keyboard, the program willaccept data from the keyboardIf input stream flows from a file, the program will acceptdata from the fileOutput stream: Data flows out of the programTo the screenTo a file Slide 6- 8Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesleycin And cout StreamscinInput stream connected to the keyboardcout Output stream connected to the screencin and cout defined in the iostream libraryUse include directive: #include <iostream>You can declare your own streams to use with files. Slide 6- 9Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-WesleyWhy Use Files?Files allow you to store data permanently!Data output to a file lasts after the program endsAn input file can be used over and overNo typing of data again and again for testingCreate a data file or read an output file at yourconvenienceFiles allow you to deal with larger data sets Slide 6- 10Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-WesleyFile I/OReading from a fileTaking input from a fileDone from beginning to the end (for now)No backing up to read something again (OK to start over)Just as done from the keyboardWriting to a fileSending output to a fileDone from beginning to end (for now)No backing up to write something again( OK to start over)Just as done to the screen [...]... only to the stream named in the call Slide 6- 3 Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Overview 6.1 Streams and Basic File I/O 6.2 Tools for Stream I/O 6.3 Character I/O 6.4 Inheritance Slide 6- 45 Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Manipulators  A manipulator is a function called Introduction to Polynomial and Rational Functions Introduction to Polynomial and Rational Functions By: OpenStaxCollege 35-mm film, once the standard for capturing photographic images, has been made largely obsolete by digital photography (credit “film”: modification of work by Horia Varlan; credit “memory cards”: modification of work by Paul Hudson) Digital photography has dramatically changed the nature of photography No longer is an image etched in the emulsion on a roll of film Instead, nearly every aspect of recording and manipulating images is now governed by mathematics An image 1/2 Introduction to Polynomial and Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-WesleyChapter 6I/O Streams as an Introduction to Objects and Classes Slide 6- 3Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-WesleyOverview6.1 Streams and Basic File I/O 6.2 Tools for Stream I/O6.3 Character I/O6.4 Inheritance Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley6.1Streams and Basic File I/O Slide 6- 5Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-WesleyI/O StreamsI/O refers to program input and outputInput is delivered to your program via a stream objectInput can be fromThe keyboardA fileOutput is delivered to the output device via a streamobjectOutput can be to The screenA file Slide 6- 6Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-WesleyObjectsObjects are special variables thatHave their own special-purpose functionsSet C++ apart from earlier programming languages Slide 6- 7Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-WesleyStreams and Basic File I/OFiles for I/O are the same type of files used tostore programsA stream is a flow of data.Input stream: Data flows into the programIf input stream flows from keyboard, the program willaccept data from the keyboardIf input stream flows from a file, the program will acceptdata from the fileOutput stream: Data flows out of the programTo the screenTo a file Slide 6- 8Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesleycin And cout StreamscinInput stream connected to the keyboardcout Output stream connected to the screencin and cout defined in the iostream libraryUse include directive: #include <iostream>You can declare your own streams to use with files. Slide 6- 9Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-WesleyWhy Use Files?Files allow you to store data permanently!Data output to a file lasts after the program endsAn input file can be used over and overNo typing of data again and again for testingCreate a data file or read an output file at yourconvenienceFiles allow you to deal with larger data sets Slide 6- 10Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-WesleyFile I/OReading from a fileTaking input from a fileDone from beginning to the end (for now)No backing up to read something again (OK to start over)Just as done from the keyboardWriting to a fileSending output to a fileDone from beginning to end (for now)No backing up to write something again( OK to start over)Just as done to the screen [...]... only to the stream named in the call Slide 6- 3 Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Overview 6.1 Streams and Basic File I/O 6.2 Tools for Stream I/O 6.3 Character I/O 6.4 Inheritance Slide 6- 45 Copyright © 2007 Pearson Education, Inc. Publishing as Pearson Addison-Wesley Manipulators  A manipulator is a function called Introduction to Exponential and Logarithmic Functions Introduction to Exponential and Logarithmic Functions By: OpenStaxCollege 1/3 Introduction to Exponential and Logarithmic Functions Electron micrograph of E.Coli bacteria (credit: “Mattosaurus,” Wikimedia Commons) Focus in on a square centimeter of your skin Look closer Closer still If you could look closely enough, you would see hundreds of thousands of microscopic organisms They are bacteria, and they are not only on your skin, but in your mouth, nose, and even your intestines In fact, the bacterial cells in your body at any given moment