A dissertation submitted to the Faculty of Engineering, University of the Witwatersrand, Johannesburg, in fulfillment of the requirements for the degree of master of Science in Engineering. / A software package was written under the X Window System, Version 11, to assist in manual stereopsis of multiple views. The package enables multiple high resolution (2000 by 1500 pixels and higher) black and white photographs to be viewed simultaneously. Images have adjustable zoom windows which can be manipulated with the pointing device. The zoom windows enlarge to many times the resolution of the image enabling sub-pixel measurements to be extrapolated by the operator. A user-friendly interface allows for fast pinhole camera calibration (from known 3D calibration points) and enables three dimensional lines, circles, grids, cylinders and planes to be fitted to markers specified by the user. These geometric objects are automatically rendered in 3D for comparison with the images. The camera calibration is performed using an iterative optimisation algorithm which also tries multiple combinations of omitted calibration points. This allows for some fault tolerance of the algorithm with respect to erroneous calibration points. Vector mathematics for the geometrical fits is derived. The calibration is shown to converge on a variety of photographs from actual plant surveys. In an artificial test on an array of constructed 3D coordinate markers, absolute accuracy was found to be 1 mm (standard deviation of the Euclidean error) for a distance of 2.5 meters from a standard 35 mm camera. This translates to an error of 1.6 pixels in the scanned views. Lens distortion was assumed to be negligible, except for aspect ratio distortion which was calibrated for. Finally. to demonstrate the efficacy of the package, a 3D model was reconstructed from ten photographs of a human face, taken from different angles. / AC2017

An often overlooked area of graphics is the ability of application programs to create graphical images. Many programs exist which allow creation interactively, but few offer the same ability for noninteractive application programs. By allowing an application program to create graphical images more user friendly programs may be created by programmers. / Department of Computer Science

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1990. / Vita. Abstract. Includes bibliographical references (leaves 52-54). Also available via the Internet.

Thesis (M.S.)--Rochester Institute of Technology, 1993. / Typescript. Includes bibliographical references (leaf 69).

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1992. / Vita. Abstract. Includes bibliographical references (leaves 108-113). Also available via the Internet.

published_or_final_version / Computer Science and Information Systems / Master / Master of Philosophy

by Raymond Cheuk-kuen Chen. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1994. / Includes bibliographical references (leaves 157-160). / Chapter 1. --- INTRODUCTION --- p.8 / Chapter 1.1. --- Windowing System --- p.8 / Chapter 1.2. --- Fonts --- p.10 / Chapter 1.2.1. --- Bitmap Fonts --- p.11 / Chapter 1.2.2. --- Outline Fonts --- p.12 / Chapter 1.3. --- Different font support models --- p.15 / Chapter 1.3.1. --- Supported by applications --- p.15 / Chapter 1.3.2. --- Supported by windowing system --- p.17 / Chapter 1.3.'3. --- Supported by a dedicated server --- p.19 / Chapter 1.4. --- Issues of Chinese Font Support --- p.20 / Chapter 2. --- OVERVIEW OF X WINDOW SYSTEM --- p.22 / Chapter 2.1. --- Introduction --- p.22 / Chapter 2.2. --- Architecture --- p.23 / Chapter 2.3. --- Font Management in the X Window System --- p.23 / Chapter 2.3.1. --- Before X Version 11 Release5 --- p.24 / Chapter 2.3.2. --- In X Version 11 Release5 --- p.25 / Chapter 2.3.3. --- Portable Compiled Format --- p.25 / Chapter 2.3.4. --- Font Server --- p.26 / Chapter 2.3.5. --- Font Management Library --- p.28 / Chapter 2.4. --- Internal Code --- p.29 / Chapter 3. --- CHINESE FONT SERVER --- p.30 / Chapter 3.1. --- Motivation --- p.30 / Chapter 3.2. --- Font Server Architecture --- p.31 / Chapter 3.2.1. --- Device Independent Font Server layer(DIFS) --- p.32 / Chapter 3.2.2. --- Operating System layer(OS) --- p.32 / Chapter 3.2.3. --- Font Management Library(FML) --- p.33 / Chapter 3.2.4. --- Font Path Element --- p.34 / Chapter 3.2.5. --- Font File Renderer --- p.35 / Chapter 3.2.6. --- Font server Renderer --- p.36 / Chapter 3.3. --- Implementation of Chinese Font Server --- p.36 / Chapter 3.3.1. --- Font data and code set --- p.36 / Chapter 3.3.2. --- Registering a new font reader --- p.38 / Chapter 3.3.3. --- Font specific functions --- p.42 / Chapter 3.3.4. --- Load-All Scheme --- p.43 / Chapter 3.3.5. --- Demand-Loading Scheme --- p.44 / Chapter 3.3.6. --- Embedding of font rasterizer --- p.44 / Chapter 3.4. --- Test Results --- p.45 / Chapter 3.4.1. --- X Application Tests --- p.45 / Chapter 3.4.2. --- Demand-Loading Test --- p.49 / Chapter 3.5. --- Some Remarks --- p.53 / Chapter 4. --- OVERVIEW OF PRINTING SYSTEM --- p.54 / Chapter 4.1. --- Motivation --- p.54 / Chapter 4.2. --- Design Considerations --- p.56 / Chapter 4.2.1. --- Modification of the X server --- p.56 / Chapter 4.2.2. --- Embed the printing system into the font server --- p.57 / Chapter 4.2.3. --- Distributed Architecture --- p.58 / Chapter 4.3. --- System Architecture --- p.60 / Chapter 4.4. --- Printer Server --- p.61 / Chapter 4.5. --- Font Server --- p.63 / Chapter 4.6. --- Printing Services Protocols --- p.63 / Chapter 4.7. --- X Window System Server --- p.65 / Chapter 4.8. --- Printer Server Library --- p.65 / Chapter 4.9. --- Client Applications --- p.65 / Chapter 5. --- DESIGN AND IMPLEMENTATION OF A PRINTER SERVER --- p.67 / Chapter 5.1. --- Objects identification --- p.67 / Chapter 5.1.1. --- Dispatcher (dispatcher) --- p.68 / Chapter 5.1.2. --- Communication Channel (ComChannel) --- p.68 / Chapter 5.1.3. --- Font Cache Manager (FnCache) --- p.69 / Chapter 5.1.4. --- PrnFont (PrnFont) --- p.69 / Chapter 5.1.5. --- Per-Font Cache (CacheStruct) 一- --- p.70 / Chapter 5.1.6. --- Font Server (FnServer) --- p.71 / Chapter 5.1.7. --- Client Manager (LRUList) --- p.71 / Chapter 5.1.8. --- Client Record (ClientRec) --- p.71 / Chapter 5.1.9. --- Printer Driver (PrnDriver) --- p.71 / Chapter 5.1.10. --- Down Loaded Font Table (DownLoadedFont) --- p.72 / Chapter 5.1.11. --- Request Header (reqHeader) --- p.72 / Chapter 5.1.12. --- Generic Reply(replyGeneric) --- p.74 / Chapter 5.2. --- Objects Organization --- p.74 / Chapter 5.2.1. --- Server Control Subsystem --- p.75 / Chapter 5.2.2. --- Client Management Subsystem --- p.78 / Chapter 5.2.3. --- Request Handling Subsystem --- p.84 / Chapter 5.2.4. --- Font Managing Subsystem --- p.86 / Chapter 6. --- SAMPLE PRINTER DRIVER --- p.94 / Chapter 6.1. --- Printer Control Languages --- p.94 / Chapter 6.1.1. --- Structure of PCL Command --- p.95 / Chapter 6.1.2. --- PCL Command Example --- p.97 / Chapter 6.2. --- Printer Font Resources --- p.98 / Chapter 6.3. --- Traditional Font Handling Methods in a Printer Driver --- p.99 / Chapter 6.4. --- Soft Font Creation in PCL Printer --- p.101 / Chapter 6.4.1. --- Font ID number --- p.102 / Chapter 6.4.2. --- Font Descriptor --- p.102 / Chapter 6.4.3. --- Character Code - --- p.104 / Chapter 6.4.4. --- Character Descriptor --- p.105 / Chapter 6.4.5. --- Character Bitmap Data --- p.107 / Chapter 6.5. --- New font downloading schemes for double-byte fonts --- p.107 / Chapter 6.5.1. --- Terminology --- p.108 / Chapter 6.5.2. --- Underlying Concepts of Algorithm One --- p.109 / Chapter 6.5.3. --- Algorithm One --- p.111 / Chapter 6.5.3.1. --- Code Mapping --- p.112 / Chapter 6.5.3.2. --- Example --- p.114 / Chapter 6.5.3.3. --- Memory Consideration --- p.115 / Chapter 6.5.4. --- Algorithm Two --- p.117 / Chapter 7. --- EXPERIMENT RESULTS AND DISCUSSIONS --- p.121 / Chapter 7.1. --- Cache Test --- p.121 / Chapter 7.2. --- Printer Driver Test --- p.125 / Chapter 7.2.1. --- Testing with 10 points font --- p.126 / Chapter 7.2.2. --- Testing with 12 points font --- p.129 / Chapter 7.2.3. --- Testing with 15 points font --- p.131 / Chapter 7.2.4. --- Testing with 18 points font --- p.134 / Chapter 7.3. --- Time Measurement --- p.136 / Chapter 7.4. --- Discussion --- p.139 / Chapter 7.5. --- Further Improvement --- p.143 / Chapter 8. --- CONCLUSIONS --- p.145 / APPENDIX A. PRINTER DRIVER CLASS --- p.147 / APPENDIX B. SAMPLE OUTPUT --- p.149 / REFERENCES --- p.157

The X Window System is an industry-standard software system which facilitates programmers to develop portable graphical user interfaces. This thesis describes an image processing tool developed under the X Window System. A multiwindow image display software with image editing and improvement functions is developed. The software has four modules: environment generation, image creation, image editing and image improvement. The environment generation module creates working windows, scrollbars, dialogbox and pulldown menu buttons, and tracks mouse cursor positions. The working windows are three adjacent windows allowing display of three different images simultaneously. The dialogbox provides an interface between the user and the program, such as input new image and parameters. The pulldown menus offer various selections of image processing functions. A pair of scrollbars are also added to allow users to move the magnified image up, down, left and right so that the full picture can be viewed. The image creation module can build colormap, load image data file, convert pixel values to screen color values, create image, and display image on the screen of a workstation. The program can read either sun.rasterfile format or a plain data file. If a plain data file is detected, the software can transform it to sun.rasterfile by adding an appropriate header and a colormap. There are two kinds file saving features: screen capture and store. The screen capture allows the user to save that part of image displayed on the screen. The store function saves the entire image which may be either the screen size or bigger size image (e.g. merged or zoomed image). The image editing module is equipped with the functions for zooming (in or out) , merging, rotating and restoring images. The merge function constructs a new image based on the user selected or input image from the dialogbox. The rotation center of an image can be any point selected by user's clicking mouse button, and the rotation angle is supplied by user in the dialogbox. The image improvement module consists of some image point transformation and image enhancement functions. This software package is easier to use than existing tools for image processing. It has been used in the image processing projects and related educational purposes. The software provides a framework and can be easily extended to other potential applications.

Thesis (M. Phil.)--University of Hong Kong, 2001. / Includes bibliographical references (leaves 80-84).

X windows is a graphic display management system. It is designed to work on a variety of machines and display adapters, however it is not designed for terminals with local graphics capabilities. X windows can be made to work on this type of terminal, although in a slower and restricted form. The problem with designing a variation of X for these terminals is the translation from X requests to native graphics commands, and the mapping of terminal input into X events. These implementation issues are discussed and example code is provided. / Department of Computer Science