Generation and Animation of Perspective Views
Contents
1. yY 1 1 OpenGL library Java uaz Compile dae MingW Compiler Windows UNIX Acknowledgement This project is successful since the help of many people who made our working easier with words of encouragement and more knowledge to expand theories and ideas The most important person are Sally E Goldin Ph D our advisor and Kurt T Rudahl M Sc who gave us many concepts knowledge support sug2. Sally E Goldin Ph D a a a Cd 2549 3 fa Yq Y Y Y v y aA 1 A a H a A AA 2
3. 3 DEM file 3 Satellite image v A aA A a w A A JA
4. a Yq Y o a y wv aR Y w a A A A a Y A w w 3D Perspective Views
5. 10 We have learned many concepts and algorithms from our project that include polygon mesh texture mapping animation of 3D and the general concepts of computer graphics We have obtained knowledge and information about remote sensing image especially in DEM and satellite images which we used as the input to the program We have learned and practiced using MingW as compiler that is development environment that provides UNIX like capabilities on Windows We have learned to use OpenDragon program that is a remote sensing image processing package and also practiced using OpenDragon toolkit for reading header of Open Dragon file We have learned about linking together code in different language We have practiced creating runtime object in Java code to link source code of Java language to C language We have learned to work in a team manage our time and to have more responsibility We also learned to handle the problems which we have never faced before by searching information on internet consulting with our advisor and asking the people who know We have improved and developed our English skill in writing speaking reading and listening 6 4 Problems 1 We need to collect data from two dimensions for using to create the three dimension but normal two dimension can not provides enough information for create three dimensions Then we use DEM data to create three dimensions because DEM data give information about the elevati
6. 10 News online available http www mesa3d org Mesa Home Page_files news htm 2006 September 8 Polygon Surfaces online available http escience anu edu au lecture cg surfaceModeling polygon en html 2006 September 14 Working with Triangle Meshes online available http www artofillusion org docs trimeshtut index 2006 September 4 Computer Graphics online available http www cs su ac th rawitat teaching graphics06 coursefiles files 3_viewing pdf 2006 September 19 48 13 14 15 16 17 18 19 20 Texture Mapping online available http earthscape org t1 fre03 fre03 11 htm 2006 September 12 2D and 3D Projections online available http www cs umu se kurser TDBC07 HT05 handouts HO lecture4 pdf 2006 September 12 Chapter 1 Fundamentals of Remote Sensing online available http www profc udec cl gabriel tutoriales rsnote cp1 cp1l 1 htm 2006 September 11 Satellite Image online available http landsat gsfc nasa gov references glossary html 2006 September 12 Articles and Resources online available http www gamedev net reference 2006 September 15 Perspective Texture Mapping Part 3 Endpoints and Mapping online available http www d6 com users checker misctech htm 2006 September 18 The Map Frame online available http www mathworks com access helpdesk
7. Pixel Areas to Texture space Use Case Diagram Flow Chart Module AspenDem img Simple 3D Model Texture Mapping in a True Color Mode Texture Mapping in a Gray Scale Mode Green Band Texture Mapping in a False Color Mode Rotation of the 3D Model Translation of the 3D Model Zooming In Zooming Out Adjustment of Vertical Scale User Interface Pages CO NN N Nn r 13 14 15 17 18 25 29 31 33 34 35 35 36 37 38 39 40 40 Vi Figure 5 11 Figure 5 12 Figure 5 13 File Selection Box Warning Message Display Window Pages 41 42 42 vii Table 2 1 List of Table Spectral Sensitivity of Landsat 7 Bands Pages Vili Chapter 1 Introduction The most common picture about terrain is 2D such as photographs satellite images and maps A two dimensional representation has only a single viewpoint so it does not provide enough information for a user We will present a 3D model instead 2D to provide more information by using techniques in the fields of computer graphics and computer animation The software developed in this project creates a 3D model starting by simulating a 3D model of the terrain from a digital elevation model DEM Then it uses texture mapping methods to map the pattern from satellite image to 3D model surface to show more information about terrain for the user When the user gets a 3D model that has a realistic appearance afterwards we can rotate it by using 3D animation to
8. RGB mode The combination of three bands gives a natural color result when the red band is used for the red image component the green band for the green image component and the blue band for the blue image component If the arrangement of bands does not follow this pattern the result will be a false color image The result from this process shows a 3D model that has a realistic appearance because user can see the landform of this terrain 3D model The process to interact between the user and this program This process is controlled via user interface The user can choose input files via Java interface and can adjust display by zoom in zoom out adjust vertical scale and rotate model via the display window The user can control these by using mouse 6 2 Discussion In implementation phase we have changed some parts from design phase 1 We have changed the facility to create user interface from WxWin to Java language WxWin is a package that we have never learned or used We would need to spend the long time to learn it Hence we decided to use Java language instead of WxWin because we have used Java language to create user interface We thought it can help us to reduce the implementation time Furthermore it has ability to create function of user interface coincident our requirement and also can connect to C language with creating runtime object then created string variable to receive command line for running the program follow i
9. each object has the own coordinate reference frame at the origin 0 0 0 These references frames are called object coordinates modeling coordinates local coordinates or master coordinates The individual object will be taken to the appropriate location that maybe has another individual object in the same scene This scene reference frame is called world coordinates For example a bird will be located in the sky and a tree will be located on the ground in the same scene A bird and a tree will have a new position that is referenced by world coordinates To display the object the world coordinates must be converted to viewing coordinates to show the desired view we want of the scene World coordinates are based on the position and orientation for a view plane that corresponds to a camera film plane The object locations are transformed to a 2D projection of the scene The scene is stored in normalized coordinates the graphic representation which is independent of the coordinate range for any specific output device To render the object on a device the normalized coordinates that are referred to normalized device coordinates are converted to show on the display device The 10 coordinates systems for display devices are called device coordinates or screen coordinates 2 6 2 Polygon Surface Representation Polygon surface representation is the most commonly used method in computer graphic systems It simplifies and speeds up the surface re
10. escience anu edu au lecture cg surfaceModeling polygon en html A 3D triangle mesh is a collection of triangles and vertices that has three vertices per polygon They are connected by their edges It can also be considered as a surface defined by a mesh of triangular facets There are various ways to represent a 3D triangle mesh such as triangle strip triangle fan and triangle list 14 There will N 2 triangles in the triangle strip if N is the number of vertices Each triangle shares an edge with the previous triangle A triangles list will produce only N 3 triangles and does not have any edges are shared A triangle fan provide N 2 triangles again with sharing the vertex for all triangles polygon Figure 2 8 A Quadrilateral Mesh Source http escience anu edu au lecture cg surfaceModeling polygon en html A quadrilateral mesh is a set of polygons with four sides and four vertices They are connected by ther edges It provides N 1 x M 1 quadrilaterals from N x M array of vertices This project uses a triangle mesh because when a polygon has more than three vertices all vertices may not lie in the same plane This can cause confusion to calculate because the shape of the polygon may be changed from original polygon Hence using triangles mesh is safe and many hardware and software systems support it 2 6 3 Texture Mapping Algorithm Texture mapping is a common method to map a pattern onto a simple obj
11. make it possible to see this model in different views This result will show terrain as perspective views User will get more understanding about this terrain such as in Figure 1 1 which shows general characteristics of terrain Figure 1 1 General Idea of Perspective View Source http www photosat ca 1 1 Background Understanding the terrain landforms is important for many kinds of planning and development tasks For example if you want to build a resort on a hill you must understand and have enough information about this location where you desire to locate You must know the geography of your location distance for traveling and dangers that might happen in this area such as landslide In general the geographic images such as maps photographs or satellite images can not give enough information because they are presented in two dimensions These are represented as viewed from one direction This limits what you can see in the image and makes it hard to understand the details of image especially the general shape of the land Hence this project created a 3D model of the terrain to solve these problems by using OpenGL to generate this entire model and using MingW for compiling and running the program This model can display properties of the terrain such as width height deepness shape curve etc Moreover it can be rotated to bring more aspects of the image into view This model can help people who would like to study the
12. their desirable band User click display button to see 3D perspective view of terrain model at The interface shows 3D perspective view of terrain model at a gray scale mode 4 3 3 Scenario 3 Open File and Display Output in True Color Mode User would like to see 3D model in true color mode User need to select a DEM file and three bands of satellite images 1 2 3 4 Open program User specifies the DEM file which would like to display User specifies a Red band of satellite image file User specifies a Blue band of satellite image file 26 5 User specifies a Green band of satellite image file 6 User click display button to see 3D perspective view of terrain model at a true color mode 7 The interface shows 3D perspective view of terrain model at a true color mode 4 3 4 Scenario 4 Rotate the Terrain Model After selecting the file to display user would like to see the terrain model in a different direction 1 User click mouse on the display window as the start point for rotation and drag a mouse to the direction that they would like to see the terrain User can drag mouse in free direction They can drag to the upper side lower side right side and the left side 2 The interface shows the rotation of terrain model start at point of view at mouse clicked to mouse released in the stop point of rotation 4 3 5 Scenario 5 Adjust Vertical Scale After selecting the file to display user would like to see th
13. values from blue band are stored in B element for each pixel This gives the result which is displayed in a natural color If a gathering of texture value from three bands does not follow this the result will be displayed in a false color mode However if only one band of the satellite image is input the result will be displayed in a gray scale mode by giving the same texture value in R G and B elements for each pixel 4 Use the texture value in a texture array for mapping on the surface of simple 3D model The texture value is applied by assigning texture coordinate values to vertex of simple 3D model 5 The result from texture mapping is displayed in a display window lt 3D Perspective Views Figure 5 2 Texture Mapping in a True Color Mode 34 lt 3D Perspective Views Figure 5 4 Texture Mapping in a False Color Mode 35 5 3 Rotation of the 3D Model User can control the rotation of 3D model by mouse These are steps to control the rotation 1 User must press key R on a keyboard before using the mouse to control the rotation 2 User drags the mouse to control the rotation on X and Y axis They can drag a mouse in free direction Dragging mouse to the upper and lower side controls the rotation on Y axis Dragging a mouse to the right and left side controls the rotation on X axis 3D Perspective Views Figure 5 5 Rotation of the 3D Model 5 4 Translation of the 3D Model User can control the tran
14. 31 Send result from triangular mesh Chapter 5 Experiment 5 1 Create Simple 3D Model This part can read 8 bit per pixel and 16 bit per pixel Dragon images files and use value from this image that is value of row value of column and height value to create Simple 3D model file The procedure of this part is 1 2 User sends path of input file DEM file to this module Read input DEM file in Dragon image format img by using libdtk The libdtk function read information from header of dragon image This provides the necessary values for the program such as the number of rows the number of pixels and the data size of image Once the data size of image is known the program considers that the DEM file is 8 bit image or 16 bit image and allocates memory for one line long data buffer In each turn program read height values in all pixels from each row and collects these values to destination data buffer The procedure from 2 4 need to use libdtk to read and collect data from DEMs The values in data buffer from all turns are collected in variable array of coordinate x y and z The value of pixel is x the value of row is y and the height value is z These values in variable array of coordinate are used to simulate the simple 3D model The module for creating simple 3D model uses these values to create triangular mesh We used OpenGL function to create triangular mesh and represented this as triangle strip Th
15. Generation and Animation of Perspective Views Miss Korrapin Atichaichotikul Miss Piyana Sukanghong A Project Submitted in Partial Fulfillment of the Requirements for the Degree of Bachelor of Engineering Department of Computer Engineering Faculty of Engineering King Mongkut s University of Technology Thonburi Academic Year 2006 Generation and Animation of Perspective Views Miss Korrapin Atichaichotikut Miss Piyana Sukanghong A Project Submitted in Partial Fulfillment of the Requirements for the Degree of Bachelor of Engineering Department of Computer Engineering Faculty of Engineering King Mongkut s University of Technology Thonburi Academic Year 2006 Project Committee 0 0 eel Chairman Assoc Prof Suthep Madarasmi Ph D je 311 1 1 0 Committee Natasha Dejdumrong D Tech Sci 2 31111111111553 0 Advisor Sally E Goldin Ph D Project Title Generation and Animation of Perspective Views Project Credit 4 credits Project Participant Miss Korrapin Atichaichotikul Miss Piyana Sukanghong Advisor Sally E Goldin Ph D Degree of Study Bachelor s Degree Department Computer Engineering Academic Year 2006 Abstract The most common picture about terrain is 2D such as photographs satellite images and maps A two dimensional representation has only a single viewpoint so it does not provide enough information for a user User will find it hard to understand the detail of image such as height curv
16. ale of 3D model by a mouse These are steps to adjust a vertical scale 1 User must press key V on a keyboard before using the mouse adjust a vertical scale 2 User drags a mouse to adjust a vertical scale They can drag a mouse to the upper side on a display window to adjust a vertical scale looks higher and can drag a mouse to the lower side on a display window to adjust a vertical scale looks shorter The vertical scale of 3D model looks higher or shorter because the viewport is changes the y coordinates values range A larger the y coordinates values range makes a 3D model look shorter and a smaller y coordinates values range makes a 3D model look higher 39 3D Perspective Views Figure 5 9 Adjustment of Vertical Scale 5 7 User Interface Figure 5 2 shows the user interface for the program The interface shows the capabilities of the program which are described in this section amp Perspective Views Display Figure 5 10 User Interface 40 1 DEM File The button for insert the DEM file that used as input to display 2 Satellite images Red Band The button for insert the Red Band of satellite images 3 Satellite images Green Band The button for insert the Green Band of satellite images 4 Satellite images Blue Band The button for insert the Blue Band of satellite images 5 Display button Click to compute the selected file in all text fields to display If user selects only one band of satell
17. and Image space Source Computer Graphics with OpenGL Third Edition Donald Hearn and M Pauline Baker page 630 17 The s t texture space coordinate for 4 corners of the texture pattern is assigned to 4 spatial positions on scene and a linear transformation is used to assign color value to the projection pixel positions The parametric linear transformation provides a simple pattern for mapping position in texture space to object space u u s th a st btt c v Wus t a st b ttc x u v plu v y u v z u v Where u v are surface parameters and a point p on the surface is a function of two parameter u and v The object to image space transformation can be made by connecting of the viewing and projection transformations A mapping from texture space to pixel space has disadvantages because pixel that we use to patch does not match up with the pixel boundary It is necessary to calculate the new area of the pixel that covers the texture So texture mapping methods mostly use mapping from pixel space to texture space To avoid pixel subdivision problem it is necessary to calculate the inverse viewing projection transformation Myp and the inverse texture map transformation Mr Projected Pixel Area Mz 1 J n HM S Pixel Surface Area Rectangular Pattern Array Figure 2 11 Texture Mapping by Projecting Pixel Areas to Texture space Source Computer Graphics with OpenGL Third Edition Donald Hearn a
18. appear are not normally the colors that exist on the ground This color is represented by different wavelengths A true color image can be produced by combining and mapping the true band with primary color RGB mapping Red band to red Green band to green and Blue band to blue This project uses a satellite image to map the pattern by texture mapping method onto simple 3D model surface 2 5 Graphics Library A computer graphics library is a collection of functions designed to aid creating objects in computer graphics This also provides optimized versions of functions that handle common rendering tasks This can be operated in software and running on the CPU common in embedded systems or be hardware accelerated by a Graphics Processing Unit or GPU more common in PCs The library functions can process an image to be output for displaying on the monitor This relieves the programmer of the task of creating and designing functions of graphics program and allows them to focus on building the graphics application There are many graphics libraries available for programmers such as OpenGL Direct3D GD GKS or MESA 2 6 Algorithms 2 6 1 Coordinate Representation General graphic packages specify scenes in a standard of right handed Cartesian coordinate reference frames Several different Cartesian coordinate reference frames are used in the process of constructing and displaying a scene For the individual object such as a bird or a tree
19. bands For color Figure 5 12 Warning Message 1 Warning message The dialog box will be shown when user chooses two bands of satellite image 2 OK button The button for return to the user interface for selecting the satellite image again 3D without Texture Figure 5 13 Display Window 42 l Display window Created from OpenGL function It displays output of this program 5 8 Connection between the User Interface and the Display Connection between Java and C or C language of this program can connect by creating runtime object then create string variable to receive command line for running the C program follow input that user insert to the user interface afterward create process object to execute follow these command line 43 Chapter 6 Conclusions and Discussions 6 1 Conclusions This project is divided into three main parts 1 The process to create a simple 3D model is the first process for this program This process need the height value from DEMs files to create the simple 3D model The result from this process will show the structure of the terrain that is of interest The process to map texture mapping is a process that need the result from the previous process for mapping details of landform on it The details landform obtains from satellite images Texture mapping with one band of satellite images displays the result in gray scale mode and three bands of satellite images displays in
20. del DEM data are widely available for many locations on earth A DEM can be produced by many methods such as digitizing existing contour map or stereo analysis of aerial photographs or satellite images Most DEMs are created by remote sensing with satellites However a DEM is different from a satellite image A DEM gives information about the elevation at each point pixel grid cell while a satellite image gives information about ground cover such as a river a lake a mountain a wood etc In this project a DEM is used to generate a structure of 3D model After that it will be a simple 3D model 2 2 Texture Mapping Texture mapping is the method for adding a pattern or texture to a simple 3D model surface It is the same idea as to paint a picture onto a sketch Texture mapping makes the simple shapes have a very realistic appearance This allows a complicated pattern of the surface without adding complexity to the simple shape to represent a more details Texture image Sphere with texture Figure 2 1 Texture Mapping Source http en wikipedia org wiki Image TextureMapping png This project uses texture mapping methods to map the pattern from satellite image to 3D model surface 2 3 Animation Computer animation is creating a moving image by using the computer It relates to the theory of computer graphics and animation Computer graphics uses mathematics to create the object that the us
21. e deepness width shape etc Understanding the terrain landforms is important for many tasks such as planning the construction on any area or planning path Thus this project created a program that we call 3D Perspective Views to solve these problems This program presents the terrain model in 3 dimensions It clearly shows the 3D structure similar to real terrain by using DEM file to create 3D Model and satellite images to give detail of landform User can rotate the model to make it possible to see this model in different views Furthermore user can adjust the display by adjusting the vertical scale zooming in and zooming out The purpose of this project is to provide more details of terrain to people who interested in the geology and terrain study This program is created by using C language in MingW environment and OpenGL library as a major development library The user interface is developed by using Java programming language This program can be used in both Windows and Linux operating system 4 wv o A av a
22. e result from create triangular mesh is displayed the simple 3D model in display window The procedure from 6 7 need to use OpenGL functions for creating triangular mesh and display window lt 3D without Texture Figure 5 1 SanFranDemSub img Simple 3D Model 5 2 Texture Mapping This part handles about satellite images to map the detail on a simple 3D model The procedure of this part is 1 User sends path of input file satellite images files to read the information from header file and color values on each pixel This procedure uses the same function as reading DEM file Satellite images which is used for texture mapping needs to have the same numbers of columns and row as DEM file Both the numbers of columns and rows must be a power of two Therefore we must check the number of columns and rows before mapping If a number of columns and rows from satellite image is not a power of two we must increase the size to be a power of two But we do not use addition of image for mapping After reading values from satellite images and managing the size of image we will store color values from each pixel in texture array We use RGB color component that means each color of the texture pattern is 33 specified with three RGB values Therefore the size of the array is three width height Texture values from red band of satellite image are stored in R element texture values from green band are stored in G element and texture
23. e same way and others measure variations in gravitation and magnetic fields A satellite image can describe the details of geography such as a river a lake a mountain a wood etc 2 4 1 Types of Satellite Images There are several types of satellite images 2 4 1 1 Visible Satellite Image A visible satellite image records visible light from the sun that reflects to the satellite Visible light is roughly wavelengths between 400 and 700 nanometers Some people may be able to perceive wavelengths from 380 to 780 nanometers A visible satellite image can be represented as a gray scale image so that it can be seen with the eye You can use a computer to change it to different shades of gray or different colors Figure 2 2 Visible Satellite Image Source http en wikipedia org wiki Main Page 2 4 1 2 Infrared Satellite Image Infrared satellite image recorded by using invisible infrared radiation reflected or emitted from the earth and captured by a satellite Infrared radiation is in the wavelength range from 710 nanometers to 1 millimeter Many weather satellites measure infrared radiation You can use a computer to change it to different shades of gray or different colors Figure 2 3 Infrared Satellite Image Source http en wikipedia org wiki Main_ Page 2 4 1 3 Microwave Radar Satellite Image Microwave Radar satellite image recorded by using microwave region of the spectrum Microwave sate
24. e terrain model in a different vertical scale 1 User changes a vertical scale by use a mouse to adjust the vertical scale Dragging mouse to up direction is the increasing vertical scale and dragging mouse to down direction is the decreasing vertical scale 2 The interface displays the terrain model which is changed the vertical scale 4 3 6 Scenario 6 Zoom In the Terrain Model After selecting the file to display User would like to make a model look bigger 1 User drags mouse to the right side on display window to control zooming in the terrain model 27 2 The interface shows the terrain model at bigger size 4 3 7 Scenario 7 Zoom Out the Terrain Model After selecting the file to display User would like to make a model look smaller 1 User drags mouse to the left side on display window to control zooming out the terrain model 2 The interface shows the terrain model at smaller size 3 Close program by clicking close window button 4 3 8 Scenario 8 Move the Terrain Model After selecting the file to display User would like to move a model to other area in the display window 1 User drags mouse to the new position 2 The interface shows the terrain model on the new position 3 Close program by clicking close window button 4 4 Flow Chart This flowchart in Figure 4 2 shows the procedure of the perspective view program After receive input file DEMs and satellite images from user the program reads
25. e the ability to execute and create a Makefile used by make MingW was used as the compiler in this project is it has characteristic of portability to other operating system which means it can compile and run on both Windows and Linux This is a command for the C language It compiles hello c by using OpenGL libraries gcc 0 hello exe hello c IC mingw32 include c lib libglut32 a c lib libglu32 a c lib libopeng132 a This is a command for the C language It compiles hello cpp by using OpenGL libraries g hello cpp 0 hello exe IC mingw32 include c lib libglut32 a c lib libglu32 a c lib libopeng132 a make This command useful for compiling programs that include several source files For this command it is necessary to have a makefile Makefile is a collection of instructions that should be used to compile and link your program The makefile can contain any operating system commands and be used to automate the creation of a complicated application When you run make it will look for a file named makefile in your directory and then execute it 23 3 5 OpenDragon OpenDragon is a remote sensing image processing package which also includes a library of functions to allow users to write their own programs for use with OpenDragon This project used the OpenDragon library to read and write image files and to display 2D images and DEMs OpenDragon can combine satellite image in different bands and displa
26. ect 15 2 6 3 1 Linear Texture Patterns A 1D texture pattern is specified in a single subscript array of color values that defines is a sequence of color in a linear texture space that is referenced with a single s coordinate value For example consider a list of 32 RGB colors which references subscript values from 0 to 95 The first three elements of array store the RGB component of the first color the next three elements of array store the RGB component of the second color and so forth This set of color can be used to form or a color pattern for mapping on a model To map a linear texture pattern into a scene it is necessary to assign an coordinate value to one spatial position and another s coordinate value to a second spatial position The color array in s coordinate is used to generate a multicolored line between the two spatial positions Texture mapping uses a linear function to calculate the array positions that are assigned to the pixels to a line segment A simple color mapping method is assigned the nearest array color to each pixel If a pixel is mapped to a position between the starting array components for two colors it can be computed by a linear combination of the nearest two color components in the array 2 6 3 2 Surface Texture Patterns A surface texture pattern is defined with rectangular color pattern and position of texture space that is referenced with 2D s t coordinate values Each color is stored in a 3 s
27. er wants to display Animating is moving something which can not move itself Computer animation can use 3D computer graphic or 2D computer graphics but in this project we concentrate on 3D computer graphics Computer animation uses different techniques to create animation The animator fills the detail of the exact motion by using boolean operations on regular shapes this technique is called constructive solid geometry Another technique uses mathematical algorithms to generate a motion The animator chooses the appropriate algorithms and select necessary values such as initial values and boundary values The motion of the object is controlled by the algorithms In this project we will use mathematical algorithms to control the motion for rotating the object This allows the user to move the viewpoint to understand the data of 3D in different views and retrieve the information of the occluded objects 2 4 Satellite Image A satellite image is a photograph from a satellite that is a form of remote sensing Remote sensing is defined as the science and technology by which characteristics of objects of interest that can be identified measured or analyzed without direct contact with the object Generally remote sensing uses measurements of reflected or emitted electromagnetic radiation of the terrain of interest in a certain frequency domain Visible Light Infrared Microwaves Some systems use sound waves to collect the information in th
28. gestion including check and edit all documents which have a lot of incorrect grammars vocabulary and strategy for writing academic documentation We have a lot of thanks for both of them We would also like to gratefully acknowledge Mr Pichayapong Tontikul and Mr Wiroon Srisomburananont who gave us the consult and the suggestion for using OpenGL library in different parts of program We can solve many problems by using his suggestion and help Thank you Thanks persons who created many compiler program and open source library such as MingW compiler EditPlus Eclipse OpenGL library Java library and OpenDragon These are facility to help our project accomplished Finally very special thanks to our parent and family for give us a life a good bring up always take care support and encouragement We are really thanks for them Contents Chapter 1 Introduction 1 1 Background 1 2 Objectives 1 3 Advantages Chapter 2 Related Theories 2 1 Digital Elevation Model DEM 2 2 Texture Mapping 2 3 Animation 2 4 Satellite Image 2 4 1 Types of Satellite Images 2 4 2 Varying Resolution 2 4 3 Spectral Bands 2 5 Graphics Library 2 6 Algorithms 2 6 1 Coordinate Representation 2 6 2 Polygon Surface Representation 2 6 3 Texture Mapping Algorithm Chapter 3 Tools 3 1 OpenGL 3 2 C and C 3 3 Java 3 4 MingW and MSYS 3 5 OpenDragon 3 6 The OpenDragon Toolkit Libraries libdtk 3 6 1 Reading Dragon Image Pages o
29. help toolbox map map html access helpdesk help toolbox map creatil0 html 2006 September 18 Introduction Technical and History Perspectives of Remote Sensing online available http rst gsfc nasa govw Intro Part2_1 html 2006 September 18 49
30. hes 4 1 Requirements l Platform independent must be able to compile and run on either Windows or Linux 2 Can work for any DEM and satellite images expressed in OpenDragon format images 3 Animation must be smooth so it looks as though viewpoint is gradually changing 4 Adjustable vertical scale 4 2 Use Case Diagram This section describes use case diagram in our program Insert the DEM file Insert the satellite image Adjust the vertical scale Rotate the 3D model Resize the window Figure 4 1 Use case Diagram 4 3 Use Case Narratives This section describes use case narrative in each scenario that can be happened in our program User need to start with the scenario 1 scenario2 or scenario 3 every time they would like to use this program 4 3 1 Scenario 1 Open DEM File and Display Output User would like to see the result from a DEM file only Not need to select satellite images 1 2 3 4 Open program User specifies the DEM file which would like to display User click display button to see simple 3D model The display window shows simple 3D model 4 3 2 Scenario 2 Open File and Display Output in Gray Scale Mode User selects a DEM file and only one band of satellite image 1 2 3 Open program User specifies the DEM file which would like to display User select one band of satellite image file maybe Red band Green band or Blue band and specifies a satellite image file from
31. is to use a set of texture reduction pattern such that each reduction pattern will be one half the size of the previous pattern For example if we have 2D 16 by 16 patterns then we set up four patterns with reduction size at 8 by 8 4 by 4 2 by 2 and 1 by 1 For any view of the object the reduction pattern can be applied to minimize distortions These techniques are referred to as MIP maps or mip maps that it can translated as much on a small object Texture reduction maps are used in animation and in many other applications 19 2 6 3 5 Procedural Texturing Methods A procedural texturing method uses a procedural definition for color variations that are applied to the object It uses calculation of variation for properties or characteristics of objects This method can avoid transformation calculation in mapping array patterns to objects and decrease storage requirement that necessary when have large texture patterns is applied to scene For example wood grain or marble patterns can be simulated using procedural texturing This project uses 2D texture mapping methods to map the pattern from satellite image to 3D model surface to show the detail of landform 20 Chapter 3 Tools There were many tools used in this project These tools were very helpful This chapter discusses the tools that were used and the function of each tool that necessary for our project 3 1 OpenGL OpenGL is a software interface to graphics hard
32. ite images from three bands the output will display in gray scale mode but if user selects three bands of satellite images the output will display in true color mode 6 Minimize window Hide the window to the task bar 7 Restore Restore the window to the previous size 8 Close Close the window application My Directory Look in images w BI ie ChiangMai 1 img E indo2 img E SanFran R1 img E ChiangMai 2 img E indo3 img E SanFran R2 img My Recent E ChiangMai 3 img E indo4 img E SanFran R3 img Documents B ChiangMai 4 img E indomdm clF E SanFran R4 img ica ChiangMai S img E indomdm img fea SanFran R5 img E ChiangMaiDEM R img ri mek14 1 img E SanFrant img B def1ba clf E mek14 2 img SanFran2 img E def3ba clf E mek14 3 img E SanFran3 img le defagc clf E mekdmdm clF Ed SanFran4 img ea defccf clF mekdmdm img SanFranDemSub img B defcls clF a ratcha2 img E singapore1 img i defgeog clF E ratcha3 img fea singapore2 img IE defgra clf E ratcha5 img fea singapore3 img E deflin clf readme txt singapore_1m_tc_metadate My Computer E indot img E readme txt G K Ho File name My Directory My Network z Places Files of type Files Figure 5 11 File Selection Box 41 1 File selection box The dialog box for searching files that used as input to display Message e 1 Please select one band for gray scale or three
33. llites are usually active sensors they send a beam of radiation toward the target the earth and measure the radiation reflected back 7 Microwave radiation is in the wavelength range from 30 centimeters to 1 millimeter Microwave sensors can get images at night and see though clouds Figure 2 4 Microwave Radar Satellite Image Source http en wikipedia org wiki Main Page 2 4 2 Varying Resolution The resolution of satellite images depends on the equipment for creating the image and the distance from the ground to the satellite s orbit The resolution refers to the size of pixel on the ground If an image has a resolution of x meters per pixel you will usually not be able to see any objects smaller than x meters For example if image is 100 pixels wide and 100 pixels high and has resolution 20 meters per pixel the real area shown in the image will be 2000 meters wide and 2000 meters high High resolution means the each pixel of image has a smaller size on the ground Then in one pixel you will see the detail more clearly than for low resolution because in low resolution one pixel has a bigger size on the ground Satellite images have less resolution than aerial photography but they are cheaper to acquire than aerial photography Modern satellite images vary in resolution from 1 kilometer per pixel to less than one meter per pixel 2 4 3 Spectral Bands Spectral bands are a collection of image data at different
34. n be used to define a vector normal to the plane of the polygon that can describe orientation of a plane surface in space This vector is shown as in Figure 2 6 N A B N 1 1 1 P x y z 1 0 2 P O 1 gt O is inside Figure 2 6 The Vector Normal to the Surface of the Plane of the Polygon Source http escience anu edu au lecture cg surfaceModeling polygon en html 13 If the vertices of polygon are listed in a counterclockwise direction when viewed from outer side of the plane in a right handed coordinate system The direction to rotate the object follow by thumb points in the positive z axis direction and the remain finger bend from positive x axis to positive y axis the direction of vector N will point from inside to outside It is possible to determine whether any point is inside or outside the surface of the polygon by using Ax By Cz D equation If Ax By Cz D lt 0 the point x y z is inside the surface If Ax By Cz D gt 0 the point x y z is outside the surface 2 6 2 3 Polygon Meshes A polygon mesh is collection of vertices and polygons that specifies the shape of an object in 3D computer graphics There are many types of polygon meshes such as triangle mesh quadrilateral mesh or other simple polygonal mesh 2 4 6 8 Triangle Strip 9 1 3 5 7 2 4 8 5 Triangle List 9 4 3 6 7 2 3 Triangle Fan Figure 2 7 A 3D Triangle Mesh Source http
35. nd M Pauline Baker page 631 18 2 6 3 3 Volume Texture Patterns A volume texture patterns using 3D texture space coordinates s t r and 3D texture space is defined in the unit cube that has texture coordinates ranging from 0 to 1 0 It can be stored in a 4 subscript array which first subscript is a row position second subscript is a column position and next subscript is a depth position In particular fourth subscript is used to reference a component of color in the pattern For example assume that RGB volume texture pattern with 16 rows 16 columns and 16 depth planes It can store in array is 16 16 16 3 12 288 elements To map pattern of entire texture space to 3D model we have several way such as assign the coordinates for 8 corners of texture space to 8 spatial positions on scene of object or map plane of texture space such as depth plane to plane in scene A volume texture patterns allows internal view such as cut away display and cross sectional slices or in 3D models to be displayed with texture patterns such as a brick a cinder block or a wood materials can have the same texture patterns applied all the spatial area of the models 2 6 3 4 Texture Reduction Patterns A texture reduction pattern is used when the size of a texture object is reduced Reducing the size of the object has the effect of making the texture pattern be applied to smaller area and leads to texture distortions One way to avoid these problems
36. ndering and display of objects It uses a boundary representation that is a set of surface polygons that enclose the object interior Figure 2 5 Polygon Surface Representations Source http escience anu edu au lecture cg surfaceModeling polygon en html 2 6 2 1 Polygon Table A polygon surface is represented with a set of vertex coordinates and associated parameters Each polygon is input They are placed into a data structure that combines geometric tables topological tables and attribute tables Geometric tables contain vertex coordinates for each polygon Topological tables contain the information to arrange polygons that is the relationships between polygons Attribute tables contain the information specify the degree of transparency of the object and texture characteristics Geometric data is stored in three lists as a vertex table an edge table and a polygon table The coordinate values for each vertex are stored in a vertex table An edge table contains information of edges for each polygon defined with 11 vertices that determine endpoint of each edge This also points to the vertex table A polygon table contains edges for each polygon that can point to edge table From these three tables we can check for errors by these conditions l Every vertex must be a component of at least two edges 2 Every edge must be a component of at least one polygon 3 Every polygon must be closed 4 Every polygon must have a
37. ne nun A A 10 10 11 15 21 21 22 22 23 24 24 24 iv Pages Chapter 4 Approaches 25 4 1 Requirements 25 4 2 Use Case Diagram 25 4 3 Use Case Narratives 26 4 4 Flow Chart 28 4 5 Detail Design 30 Chapter 5 Experiment 32 5 1 Create Simple 3D Model 32 5 2 Texture Mapping 33 5 3 Rotation of the 3D Model 36 5 4 Translation of the 3D Model 36 5 5 Zooming In and Zooming Out 37 5 6 Adjustment of Vertical Scale 39 5 7 User Interface 40 5 8 Connection between the User Interface and the Display 43 Chapter 6 Conclusions and Discussions 44 6 1 Conclusions 44 6 2 Discussion 44 6 3 Skills and Knowledge from the Senior Project 45 6 4 Problems 46 6 5 Suggestion 47 References 48 Figure 1 1 Figure 2 1 Figure 2 2 Figure 2 3 Figure 2 4 Figure 2 5 Figure 2 6 Figure 2 7 Figure 2 8 Figure 2 9 Figure 2 10 Figure 2 11 Figure 4 1 Figure 4 2 Figure 4 3 Figure 5 1 Figure 5 2 Figure 5 3 Figure 5 4 Figure 5 5 Figure 5 6 Figure 5 7 Figure 5 8 Figure 5 9 Figure 5 10 List of Figures General idea of Perspective View Texture Mapping Visible Satellite Image Infrared Satellite Image Microwave Radar Satellite Image Polygon Surface Representations The Vector Normal to the Surface of the Plane of the Polygon A 3D Triangle Mesh A Quadrilateral Mesh Two dimensional Texture space Coordinates Coordinate Reference Systems for 2D s t Texture space Object space and Image space Texture Mapping by Projecting
38. nput that user insert to the user interface afterward created process to execute follow these command line The reason that we have not used JNI to link source code of Java language to C language because we try to use JNI but not success and our user interface has responsibility for getting input file only So we can connect by using this method We have changed the user interface Because we have changed the language from WxWin to Java this affected the features of the user interface We could not easily combine displaying window which was created by OpenGL function and C language to user interface which was created by Java language We decided it would be better to separate the display window and the Java control panel The Java control panel sends the control values from the user to the program and the display window only responds to display output 6 3 Skills and Knowledge from the Senior Project Doing this senior project provides many useful things for us that are development skill new knowledge concept and general skill We can distribute by these We have developed our skill about programming in C C and Java language Especially C language is programming language that we never used before We have practiced programming with C in this project We have learned and used graphic library to create computer graphic program In our project we used OpenGL library to help us for creating model of perspective views 45
39. nse for display result from all user s interaction via user interface Interaction is module that sends value of interaction from user to module which responses for processing 30 Module Read the DEM and Module Create the 3D model satellite image data Read the DEM data 6 Store the DEM data as vertex data pH r 1 1 A Read the satellite image data CI ee ahs Store the satellite image data Send path of DEM Send result from triangular Send the satellite image data Module Texture mapp Send new vertex data m Texture reson fro mapping gt Insert the satellite image Rotate the 3D model H Handle the window of user interface K gerd trot vale to manage sizeof window Handle the display of output from zoom in and zoom out t Send the control value to manage zoom inf zoom out 4 Resize the window Change the angle to animate model 4 Figure 4 3 Module Adjust the vertical scale Zoom in and zoom out tation nage roi 1 Sand the contro value to ma
40. on for interacting with any screen window system and contains many commands to helpful creating graphic program by OpenGL This project used GLUT so that the program would be device independent This project used functions of OpenGL for creating mesh polygon texture mapping and animation 3 2 C and C C and C are closely related programming languages developed for use on the UNIX operating system They are flexible languages because they are independent of hardware They have the ability of work to be equal to assembly language They are often used to write system software and applications C is a general programming language C was the C predecessor C is a small compiler and lots of free compilers The advantages C has over C are that the executables are generally smaller and the programs run slightly faster C is an object oriented programming language There is a standard library of data classes Standard Template Library STL which provides all the standard data structures like linked lists vectors etc It has a few extra features C allows the programmer to more easily manage and operate with objects using an Object Oriented Programming OOP concept C applications are generally slower at runtime and are much slower to compile than C programs The low level infrastructure for C binary execution is also larger This project used C and C languages to create the code for create perspective view 3 3 Java Ja
41. on of the earth s surface and widely available for many locations Our program has several source codes modules We used to compile our source code by use g command This command will compile just only one source code per time It makes problems that we must run this command many times to compile all source codes and we can not link all 46 source code together We solved this problem by using makefile Makefile help us to compile all source code automatically at one time when we use command make and link object that we need together 3 We use Java language to create user interface and use C and C to create perspective views It is a problem to connect module of user interface with module of perspective view So we created runtime object then created string variable to receive command line to run program afterward created process to execute follow these command line to connect Java language to C language 4 We can not embed a display window inside Java interface because a display window was created by OpenGL in part of C program A display window by OpenGL has own window It can not integrate with Java interface 6 5 Suggestion This program can be used in the real world coordinates and can be of benefit for people who are interested in geography We would like this project continue to be developed for being the better program and has more function to respond the requirement of user For the person who is interested to continue
42. on this project we think this project should be add more function such as supporting other kind of DEM and satellite images file than img file or displaying the value of the real world coordinates and the height value on each coordinate This will be useful for people who would like to see these values for analyzing geographic data 47 10 11 12 References Donald Hearn and M Pauline Baker Computer Graphics C Version Second Edition Prentice Hall New Jersey England 1994 Donald Hearn and M Pauline Baker Computer Graphics with OpenGL Third Edition Prentice Hall New Jersey England 2004 Edward Angel Interactive Computer Graphics A Top Down Approach Using OpenGL Fourth Edition Addison Wesley USA 2006 Kurt T Rudaul M Sc OpenDragon s User Manual Chapter 4 Classification Operation King Mongkut s University of Technology Thonburi 2006 IRS Gallery of Sample Images online available http www photosat ca 2006 September 7 Satellite Imagery online available http www stormsurf com page2 tutorials satimagery shtml 2006 September 12 Chapter 1 Introduction to Computer Animation online available http www siggraph org education materials HyperGraph animation rick _parent Intr html 2006 September 12 Welcome to Wikipedia online available http en wikipedia org wiki Main_Page 2006 September 12 What is Bank online available http www bank org 2002 November
43. slation of 3D model by mouse These are steps to control the translation 1 User must press key M on a keyboard before use a mouse control the translation 36 2 User drags the mouse to control the translation They can drag mouse in free direction to a new position The 3D model is moved to a new point because a viewport is changed to a new position A viewport translate to the left side of window make a 3D model seem to be translate to the right side A viewport translate to the right side of window make a 3D model seem to be translate to the left side 3D Perspective Views Figure 5 6 Translation of the 3D Model 5 5 Zooming In and Zooming Out User can control zooming in and zooming out of 3D model by mouse These are steps to control zooming in and zooming out 1 User must press key S on a keyboard before using mouse control the zooming in and zooming out 2 User drags a mouse to control zooming in and zooming out They can drag a mouse to the left side on a display window to control zooming out the 3D model and drag a mouse to the right side on a display window to control zooming in the 3D model 37 The 3D model looks bigger or smaller because the viewport is changed a size A bigger size of viewport make a 3D model look smaller and a smaller size of viewport make a 3D model look bigger Figure 5 7 Zooming In 38 Figure 5 8 Zooming Out 5 6 Adjustment of Vertical Scale User can adjust vertical sc
44. specific wavelengths These data can be used to build an image The satellite equipment is able to obtain many images of the same location at the same time in different spectral bands Each image is from a different wavelength range in the spectrum of 8 reflected or radiated electromagnetic energy For example the Landsat 7 satellite can obtain an image using satellite instruments that collects seven images at once Each image shows a specific section of wavelengths called a band at the same location at the same time Table 2 1 Spectral Sensitivity of Landsat 7 Bands Band Number Wavelength Interval Spectral Response 1 0 45 0 52 um Blue Green 2 0 52 0 60 um Green 3 0 63 0 69 um Red 4 0 76 0 90 um Near IR 5 1 55 1 75 um Mid IR 6 10 40 12 50 um Thermal IR 7 2 08 2 35 um Mid IR These seven images are not the same images Light and dark area in the images appears in different area This is because different objects on earth surface reflect different wavelengths The different dark and bright area in each band can be analyzed to identify the area such as vegetation area soil area ocean and etc Traditionally a single image in one wavelength range will be viewed as a gray scale image However a color image can be produced by combining three different black and white images and comparing wavelengths and RGB in computer to change it in different colors This color is false color because the colors that
45. t least one edge that is shared with other polygon 5 Every edge in the edge table must point to the polygon that uses it 2 6 2 2 Plane Equation A display of a three dimension object must consist of many processes such as transformation of the model and world coordinates descriptions to viewing coordinates and device coordinates identification of visible surfaces hidden line or surface and surface rendering procedure such as determine the color or shading For these processes we need to know information about orientation of surface components that can be obtain from vertex coordinate values and equations that describe the plane of polygon The constant for the plane can be calculated from this equation Ax By Cz D 0 Where x y z is point on each plane and the coefficients A B C D are constant of the plane We can find values of these coefficients from using the coordinate values for three noncollinear points in the planes as CURES Yaar ee ana ECS We can calculate the constant for the planes from this equation A D x B D y C D z 1 k 1 2 3 This equation can be solved by using Cramer s rule as A Vee xl z X Yl Nie Nie A l Ly z B x 1 z DEY L 73 23 Elz X3 y3 l X3 gt Y3 gt Z3 This equation can be rewritten as 12 A Y Z DY Z3 2 YZ 2 Be 721i Pelt XN Z3 X x C x V2 y3 2 93 Y 430 Y D V223 222 X 0321 YZ3 X M122 9221 The coefficients A B C ca
46. terrain to get more understanding than a normal image because it is like a simulation from the real landform 1 2 Objectives 1 To create a simulated 3D model of the terrain from a digital elevation model DEM to improve visualization 2 To use a Satellite image to provide textural and color detail on top of the 3D model 3 To animate the 3D model so that user can rotate it in real time to display the area from different points of view 4 To learn about 3D computer graphics and animation To learn about the basics of digital raster data DEMs and satellite images 1 3 Advantages 1 This 3D model will make it easier to understand the terrain than the normal picture so it will be useful for people who want to study the terrain It looks more realistic than normal picture It can let the user see a perspective view It can be used to analyze the structure of area that will be useful for several activities such as planning the construction on the hill or planning paths Chapter 2 Related Theories 2 1 Digital Elevation Model DEM A digital elevation model or DEM is represented in digital format that is numerical ASCII or binary file This digital format consists of detail about the elevation of the earth s surface from a known level or sea level The DEM contains only spatial elevation data in a regular grid pattern in raster format It can be applied for many applications such as analysis for creating a 3D mo
47. the values from these input files The value is obtained from DEMs file is used to create geometric mesh Program continues to read satellite image and use this value to map satellite image to simple 3D model which is the result from creating geometric mesh The result will be displayed in the display window If user would like to control the display by zoom in zoom out rotating and modifying scale program will recompute the output and redisplay it But if user would like to exit program program will close 28 Read DEM Create Geometric Mesh Read Satellite Image Map Satellite Image to Model Program is Depry closed Get new Point of view zoomin out rotate modify scale Recompute the output Redisplay Figure 4 2 Flow Chart 29 4 5 Detail Design This detail design shows the modules of the perspective view program The program is divided into six modules as follows 1 Read the DEM and satellite image data is a module for reading and store information from DEM and Satellite images Create the 3D model is a module for creating the simple 3D model from the vertex data which is obtained by reading DEM data Texture mapping is module for mapping the satellite image data to simple 3D model It make 3D model has a detail of landform Controller is module for handle data in this program It responses data for adjustment the vertical scale and rotation the 3D model View is module respo
48. ubscript array For example if a texture pattern is defined with 16 by 16 RGB colors the array contain is 16 16 3 768 elements Figure 2 9 show the 2D s t texture space coordinates that reference positions in an array of color values containing m rows and n columns Each position in an array can reference multiple color components Values for both s and t vary from 0 to 1 The first row of the array has the color values across the bottom of the rectangular texture pattern and the last row of the array has the color values across the top of the rectangular texture pattern The position of coordinate 0 0 references the first set of color components at the first position in the first row and the position of coordinate 1 1 references the last set of color components at the last position in the last row of the array 16 0 0 Figure 2 9 Two dimensional Texture space Coordinates Source Computer Graphics with OpenGL Third Edition Donald Hearn and M Pauline Baker page 630 Surface positions on an object can be described with u v object space coordinates and projected pixel positions with x y Cartesian coordinates Object Texture na Space j gt 1 u t Surface 4 Coordinate Parameters Coord DOUI OS Texture Surface Viewing and Projection Transformation Transformation Figure 2 10 Coordinate Reference Systems for 2D s t Texture space Object space
49. va is an object oriented programming languages developed for use on both Windows and Linux Java language is a simple language for learning and using because the most syntax to be similar with C and C languages and it is not complicated If the person has ever used C or C languages they can easily understand the syntax of the Java language Java is a robust language because it provides exception handling to handle some mistakes of program while program is running Moreover Java has automatic garbage collection so the programmer does not have to handle memory management 22 Java incorporates both interpretation and compilation The source text file program is compiled to the machine code called bytecodes for the Java Virtual Machine JVM The JVM simulates a processor that executes the bytecodes instructions Then the JVM interprets the bytecodes So the bytecodes can be run on any platform on which a JVM has been developed This project uses the Java language to create the code for the user interface 3 4 MingW and MSYS MingW is a development environment that provides UNIX like capabilities on Windows In particular it provides an implementation of the gcc Gnu C Compiler and also has commands to support Java language This project used MingW to create software that can be compiled and run on both Windows and Linux MSYS is minimal system MingW is often used together with MSYS It provide POSIX Bourne configure scripts that giv
50. ware It provides a large and efficient collection of device independent functions for creating computer graphic displays It is designed to be hardware independent This interface consists of about 150 distinct commands that are used to specify the objects and operations need to create two dimension and three dimension applications OpenGL is available on most computer systems and is used widely OpenGL is designed for using a program written in C or C but it can also be used with other programming language such as Java Delphi Perl Ada or FORTAN The general purpose of OpenGL is to provide users with a variety of function for creating polygon meshes and manipulating pictures It can create primitives object such as points lines segments or polygons and can manipulate many complex methods such as two dimension and three dimension transformation viewing method perspective projection spline generation mesh polygon generation interactive mouse input surface rendering texture mapping or animation techniques Libraries of OpenGL include the OpenGL Utility Library GLU GLU contains basic commands to use in OpenGL It exists in all OpenGL implementations However it is not possible to create the display window with the basic OpenGL functions Window management depends on the computer used The OpenGL Extension to the X window system GLX provides a set of window management for X window The OpenGL Utility Toolkit GLUT provides a set of functi
51. y the result that make user easier to understand the detail of satellite image and also can show the height value of each pixel on DEM images 3 6 The OpenDragon Toolkit Libraries libdtk The OpenDragon Toolkit Libraries consist of several libraries of functions and tool which are used in creating Dragon and are also useful for developer to write their own programs for use with OpenDragon The libdtk modules are written in C and C The developer can write own program in either C or C The methods to link your program to libdtk are necessary to include libdtk h libdtk header file in source code and link to the suitable libraries for your source code at least should be wfutl a This project used libdtk in our project for module of creating simple 3D model and texture mapping The input files for our program need to be DEMs and satellite images Both should be OpenDragon images format img The libdtk provides function that we need for reading OpenDragon image file 3 6 1 Reading Dragon Image The sequence for reading a Dragon input file is 1 Open the file and read the header metadata information consists of number of rows number of column and Bit of image 2 Based on the header information create a one line long data buffer Cycle through the rows reading and processing each in turn 4 Close the input image Unnecessary if your program will be exiting immediately 24 Chapter 4 Approac
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