First chapter of OpenDragon user manual
Contents
1. histogram of the water pixels in your image create a mask image using Classify gt Recode based on your classified image with all non water pixels recoded to zero Then specify that mask as the mask image in Utility gt Histogram All of the operations which permit use of a mask image generally most of the Enhancement and Classification operations provide a field to specify a mask image file name If this field is left blank no mask will be applied 1 3 6 Color Schemes and Color Files A color scheme in Dragon terminology is an association between each of the 256 possible image data values 0 to 255 and the color in which pixels with that value should be displayed A color scheme may assign the same color to more than one data value Frequently a contiguous range of values will be assigned to the same color for example all values between 16 and 31 might be assigned to light green You can however assign the same color to dissimilar image data values This sort of color scheme is frequently used for special effects Color schemes are stored in color files until they are used Color files can have any name up to eight characters long Their extension filetype must be CLF You should not create or modify any color files with names of the form DEFxxxxx CLF These are standard color files that Dragon uses in various operations Dragon includes an operation for defining and modifying color schemes and saving them in color files Thus you2. Dragon operations are available to allow you to view information about images signatures and so on as well as graphical non image information such as histograms scatterplots and line profiles This sort of information is displayed in a report window The results tables created by classification operations are also shown in report windows Report windows can be dismissed when you are finished with them chapt1 html page 18 at 11 Jan 2006 16 21 Error and Message Boxes As is the case with most Windows applications Dragon uses popup message boxes to communicate the existence of error or warning conditions Usually these boxes have a single button labeled OK for you to dismiss them Occasionally they will require that you make a choice e g Exit versus Continue 1 4 2 Dragon Interface Modes Dragon s user interface design accommodates varying levels of skill and experience by providing two quite different modes of operation within the same program For users new to Dragon to remote sensing image processing or to computers the program offers the Menu mode of operation Dragon menus gives detailed and explicit information and instructions about each step needed to accomplish a task It prompts for each piece of information that you must supply and gives immediate feedback if you make an error Menu operations are discussed in the following section The Menu mode offers considerable assistance to a new user H
3. a dropdown list control also called a combo box causes the choice list to drop down Pressing the lt Home gt key in a field that holds some data clears the field Left and right arrow keys move the insertion cursor within the field Pressing the lt End gt key in a field that holds some data moves the insertion cursor to the end of that data In some cases the information that you enter in one field will cause changes in other fields when you tab off the original field The most common change is to enable or disable other fields To indicate that you are finished entering parameters and want to actually execute the operation click on Ok or press the lt F1 gt key To cancel the operation click on Cancel or press either the lt F10 gt or lt Esc gt keys The bottom section of the menu client is a multi function text area This section can be used to display help image status information or command history You choose which category of information to display by clicking on the appropriate radio buttons or by pressing function keys lt F4 gt for Help lt F6 gt for Status or lt F7 gt for history When the Help functionality is active Dragon displays the help message appropriate to whichever response panel field or menu item is currently under the mouse not necessarily the field that currently has focus Thus you can run the mouse from the top to bottom of a response panel and get information on all the parameter fiel
4. a parameter value includes spaces e g in setting the Comment field in the Dragon header you should enclose entire parameter value in quotation marks e g CMT TM Band 2 of central Bangkok uncorrected Execute Code In the Command mode as in the Menu mode Dragon does not execute the operation you have chosen until you are ready An explicit Execute Code is necessary since it may take more than one line of input to specify all parameters To execute a command in Command mode press lt F1 gt or type the following at the end of the command preceed by at least one blank dash then period Because the Command mode uses an explicit Execute Code you can change your mind about parameter values you have entered Suppose you entered the following command string D 1BA F BANGKOK2 H N Notice that spaces or carriage returns must separate each command p specifier or parameter value from the others items in the command string This example requests that no histogram stretch be done Since the Execute Code was not entered Dragon does not immediately perform the display operation Instead it waits for more parameter input and or the Execute Code Suppose you change your mind and decide that you wanted the automatic linear stretch after all You could type on the command line H L The newly specified value would replace the one you typed in previously The Execute Code would cause Dragon to start the actual processing for the
5. digital data into a visual image Both digital and visual image representations of remotely sensed data have certain advantages Visual images are relatively easy for humans to analyze and interpret The visual representation makes it possible for the human analyst to see spatial patterns in data and recognize objects or areas based on their appearance and spatial relationships This sort of global relational information is difficult to extract from a set of numbers However there is information in a remotely sensed image that is not directly available to the human perceiver Distortions sensor defects and other sources of noise mask some of the information in an image Important patterns of information exist that can be detected only chapt1 html page 2 at 11 Jan 2006 16 21 by combining data from several wavelengths of reflected radiation Manipulations to minimize noise or reveal multi dimensional patterns are difficult or impossible to perform optically or photographically on the visual form of the image Such manipulations are relatively easy to perform on the digital form of the image data using a computer based digital image analysis system A digital image analysis system is a combination of computer hardware and software that can display transform and combine image data so that the human analyst can extract as much information as possible The system maintains and manipulates data in numeric digital form but displays it in visual form T
6. format and save them in the designated file chapt1 html page 24 at 11 Jan 2006 16 21 To capture all or part of the image to the Windows clipboard chooose File gt Copy If you want to copy the entire viewport to the clipboard press lt F1 gt Otherwise place the mouse cursor on the image at the upper left corner of the area that you want to capture Press the left mouse button and drag the mouse to the lower right corner of the area you want to select A flexible box will follow the mouse When you release the mouse button the box will disappear The viewport will copy the data included within the box to the clipboard From there you can past the data into graphics programs or word processing documents The viewport also offers a Help menu In this menu the Help gt Program item displays an About Box showing the program s version and copyright information as well as information about contacting the manufacturer The Help gt Status item pops up a text box with a variety of useful information about the currently displayed image including its dimensions At any time that there is an image displayed in a viewport you can find out the X pixel and Y line coordinates of any point in that image As you move the mouse cursor over the image two fields at the bottom right of the viewport display the continuously updated coordinates of the cursor On the other hand the viewport only accepts point selections clicks at very specific time
7. of these files is not important to the user and has not been included in this manual One special category of file which Dragon creates are those with any file extension including one or more dollar signs These files are intended to be temporary that is they are usually deleted automatically by the Dragon software If you see any of these files in your directories when Dragon is not running you may delete them without loss On the other hand you should not delete any such files while you are using Dragon this might create serious problems 1 3 8 Filenames and Special Filenames 1 3 8 1 Structure of a Filename The complete name of a file under the MS DOS and Windows operating systems has the appearance C PPP AA TTTT HH NODENAME EXT This name consists of four parts The drive letter shown as C in the example is the disk drive where the file resides The drive letter is followed by a colon The path shown as PPP AA TTTT HA in the example consists of a list of directories and subdirectories separated by the backslash character This path specifies the location in the directory tree on the specified drive where the file is located The node name shown as NODENAME in the example is the name which actually identifies the desired file Usually when one refers to a file name one is talking only about the node name portion In Windows node names can contain almost any character including blanks When you crea
8. of the numerous and large data files found in image processing rather than keeping a copy of these files on each computer Of course there is some cost to balance this benefit a network is much more complex to administer than a collection of isolated computers and the data access may also be slower than if all the files were kept locally In order for the local Dragon user to access data files on the network it is only necessary to specify the location where these files are to be found The network generally appears to the user just like an operating system drive or directory To access the network data files simply supply the network drive and path along with the file name as described in the preceding section There is one complication here If several different users are writing files to the network file server it is almost inevitable that sooner or later two users will try to write different files with the same name or will in some other manner get in each other s way Most Dragon data file operations involve reading rather than writing files so that most operations can be executed over the network without this problem arising You should be aware that you may not be permitted to write files to the network file server Because of this restriction we recommend that the default file creation path be set to a local directory rather than to a LAN address 1 3 10 Inputting Data to Dragon Digital image data must be made available to Drago
9. the chapter on Utility operations The most important header fields that you can list and or modify are Identifying Fields Number of Lines How many lines are in the image represented by this file Super OF how long each line is in pixels Pixels Line 8 P File Type I if normal image file C if classified image L if GIS layer or rasterized vector file Scene a text label that describes the primary location from which the data was Identification recorded should be the same for all bands of a given scene Subscene a second text label that identifies a subset of the primary location from Identification which the data was recorded should also be the same for all bands of a given scene Band Number a label usually but not necessarily a number that identifies the band if any the image represents Source a three character code identifying the Dragon operation that created the file Comment a 45 character phrase with any additional identifying information you wish Color File Name to enter Optional name of color scheme file to be used by default in displaying the image chapt1 html page 8 at 11 Jan 2006 16 21 Statistical Fields Mean value arithmetic average of data in file to nearest whole number Maximum value largest data value in file range 0 to 255 Minimum value smallest data value in file range 0 to 255 Variance value a measure of the spread of values around the mean ne ate another measure of spread Devia
10. the down arrow key Dragon displays the next line from the history When you get to the first or last lines in the history continuing to press the arrow key will not change the text displayed in the command line Note that the history will contain the command line equivalent of all the commands you have executed in this Dragon session whether in Menu or Command mode Thus you can use the command constructed in response to a Menu mode operation as the basis for a Command mode operation by recalling the earlier command into the command line as described above You may notice that when it constructs commands in response to Menu mode interactions Dragon places all parameter values in quotes This is perfectly legal you do not have to remove the quotation marks 1 4 5 Script Mode Operation A Dragon script is a normal text file that you create with a text editor program Script files hold Dragon commands in exactly the same format you would use in Command mode A script can contain a single command or a long series of commands There are a few restrictions on what can be done in script files but for the most part if you can use Command mode you can use scripts To actually execute a script you can type the at sign character on the command line followed by at least one space and then the name of the script file e g MYCLASS This starts Dragon reading and executing the commands in the file MYCLASS SPT Dragon knows that script fi
11. you can start to use the Command mode for some familiar operations while still using Menu mode for more unfamiliar ones The choice is entirely yours In Dragon Command mode you use the same menu choices operations parameters and parameters values as in Menu mode You just express them somewhat differently All information that you type in Command mode is typed on the command line To make the command line appear click the checkbox labeled Enable command line or press lt F2 gt The command line is a single line text entry area between the response panel area and the help status history area It is labeled CMD gt gt When the command line is visible and active Dragon still allows you to operate the menus If you select a new operation from the menu the command line will disappear and you will be returned to Menu mode On the other hand if there is a response panel displayed when you turn on the command line the panel will remain on the screen with all fields disabled Even though the fields are disabled you can still view the help messages for each field This can assist you as you work to construct a Dragon command in the command line area Command mode input consists of four kinds of items Commands are short sequences of characters that typically are abbreviations of menu labels All the top level menus have single letter commands Other menu items have three letter commands For example D is the command to identify the Displa
12. a conceptual perspective the current Dragon version works exactly the same way as previous versions 1 3 4 Coded Image Files A standard image file is assumed by Dragon to be radiometric data derived from a sensor The numbers which represent each image element are therefore physical measurements of the emitted or reflected radiation received by the sensor and arithmetic operations such as histogram normalization can be reasonably to these measurements Some files however have the same structure as radiometric image files but the numbers are codes or category labels rather than true physical measurements They may carry order information but never magnitude information For this reason it does not make much sense to perform arithmetic operations on such coded images Dragon refers to these files as coded image files and processes them slightly differently than radiometric image files Structurally a coded image is identical to any other image a two dimensional array of numeric values where each pixel value is associated with some position on the ground Dragon will not stop you from performing arithmetic on coded files but it will warn you that you are doing something unusual Coded image files can arise in several different ways For example a classified image results from applying a classification procedure to one or more image bands A classified image is distinguished by having a C in its header File Type field and by having associ
13. agon also uses various kinds of data files To assist you in organizing and accessing your hard disk Dragon provides a facility for a default image path or default data directory This is a drive and path specification where Dragon will automatically look for any input file which you may name For example if the default data directory is C IMG and you type in answer to some question requesting an image file name a file name of BANGPHOT Dragon will look for the file C IMG BANGPHOT IMG If the file is not actually located in the C IMG directory your will receive an error message saying the file cannot be found If in fact the file is on some other directory for example on C LANDSAT you would have to specifically name the directory by typing C LANDSAT BANGPHOT You must specify a value for the default data directory during the installation of the Dragon software The default data directory can be changed while Dragon is executing by use of the File gt Preferences gt Paths command There is also a default location where Dragon will create new data files Like the default image path the initial value for this path must be specified during the installation process but can be changed via the Preferences submenu Sometimes it is useful to have these two paths refer to the same location so that you will automatically be able read files that you write without changing the directory specification 1 3 9 Local Area Networks LAN
14. ated class names When Dragon displays a classified image it will not perform any default contrast stretch since that would change the class values Also a classified image has its own associated color scheme created when you save the image after performing a classification This special color scheme which can be modified using the Utility gt Colors operation is always used to display the classified image in color unless you explicitly request a different color scheme A rasterized overlay image can be generated using the Geometry gt Vector operations and a coded layer file may be imported from a Geographic Information System GIS package These are both characterized by having an L in the header File Type field and by including somewhat different ancillary information than a classified file Dragon uses the File Type field in the image header to determine whether an image is coded or not If you want to perform some unusual operation such as a contrast stretch on a classified image you can do so by changing the value of the File Type from C to I This will fool Dragon into treating the file like a normal image Likewise you can make a normal image look like a classified image to Dragon by changing its File Type to C Dragon permits you to do almost any sort of bizarre processing but tries to protect you from doing so by accident chapt1 html page 10 at 11 Jan 2006 16 21 1 3 5 Mask Images Processing Subregions of Images Many of t
15. buted with Dragon and a a Bibliography chapter which suggests some references for further information on image processing and computers 1 3 Dragon Image Processing Concepts 1 3 1 Images and Image Files Dragon is a program that processes image data For Dragon s purposes an image is a two dimensional array of numbers each number associated with a position in the array Positions in this array are called pixels Each pixel can be identified by a set of coordinates In Dragon the vertical coordinate is usually called the line number the horizontal coordinate is called the pixel number Both the line number and pixel number coordinates start with a value of zero at the upper left corner of the image The maximum possible values of line and pixel number depend on the particular image The pixel number at a particular point on an image is also sometimes referred to as the point s X coordinate while the line number is the point s Y coordinate Image data in the Dragon system are stored in image files The image files contain the data values for each pixel line by line Image files are normal operating sytem files you can copy them rename them delete them etc Image files in Dragon can have any name up to 32 characters long without any embedded spaces However all image files must have the extension filetype IMG so that Dragon can recognize them Normally the name you give to an image file should tell you something about what the
16. can have control over the color assignments in your images On the other hand Dragon has a set of standard color schemes that often provide good results You do not have to define your own color schemes unless you want to achieve some particular effect not possible with the standard schemes chapt1 html page 11 at 11 Jan 2006 16 21 Using Utility gt Header you can store the name of a color file in the header of an image file Then Dragon will use that color scheme by default whenever you display the image Classified images always include the name of a color file in their headers as discussed in above Note that Dragon assumes that a color file recorded in an image file header is located in the same subdirectory as the image itself 1 3 7 Other Dragon Files There are several other kinds of data files used in Dragon Information on the structure of the files listed here and other files used by Dragon is included the File Formats chapter First there are signature files Signature files store training signature statistics values that are used to guide the classification process by defining typical values for each class Signature files are created by the Classify gt Edit Signatures gt Save signature operation in Classification These files can have any file name no embedded spaces but their extension filetype must be SIG The second type of subsidiary file is the polygon file Polygon files record the boundaries of training area
17. changing data with other remote sensing and GIS systems and for exchanging both raster and vector data with other computers The basic capabilities of Dragon can be augmented by means of special purpose routines created by the individual user This possibility is discussed in more detail in the Getting Images In and Out chapter and in the manuals supplied with the Dragon Programmer s Toolkit or the libdtk libraries 1 2 Overview of This Manual Dragon Documentation The User Manual is the primary documentation for the Dragon software system The complete and most up to date version of the User Manual is provided in machine readable form as a set of HTML files and a reader program supplied with Dragon provides convenient access to this manual You can also view the individual files using any browser such as Netscape In addition to the HTML version of the User Manual you may find a printed copy of some parts of the manual Note that the printed copy is not the complete user manual and in addition may be less up to date The printed version is provided only as a convenient introduction to the Dragon system Additional documentation in the form of Technical Notes Release Notes or Installation Instructions may be distributed with the software from time to time in either printed or computer readable form Check the Dragon distribution disk s for any files called READxxx ME or READxxx HTML These will contain the most up to date information on
18. chapt1 html page 1 at 11 Jan 2006 16 21 Copyright Global Software Institute and KMUTT INTRODUCTION TO OPEN DRAGON 1 1 What is Open Dragon and What Can It Do Open Dragon is a software package for personal computers that displays and manipulates images 1 e visual representations of data Although Dragon can be used for a variety of different types of visual information it is oriented primarily toward processing remotely sensed images The following section explains remote sensing image processing and discusses Dragon s image processing capabilities from a remote sensing perspective 1 1 1 Remote Sensing Image Processing Remote sensing is gathering information about some object from a distance In most common uses of remote sensing the object is the earth or some part of it and the information gathered is measured levels of electromagnetic radiation reflected or emitted from the earth at various locations A variety of sensing instruments can be used to measure and record this radiation depending on its wavelength The most commonly used sensors are aircraft borne cameras and scanning radiometers mounted on satellites orbiting the earth Remotely sensed data are routinely used for investigation management and monitoring in a wide variety of fields meteorology forestry oceanography exploration geology hydrology and water resources engineering agriculture etc Electromagnetic radiation levels can provide information on vegetation de
19. display operation Note Dragon allows you to use lt F1 gt in the Command mode as an alternative to to provide consistency with the menu mode The dash dot Execute Code is the only way to start execution from inside a command script however The examples above demonstrate how Command mode input strings are constructed A full command requesting an operation will consist of the command for that operation a set of p specifiers each followed by its value s and finally the Execute Code You can insert carriage returns anywhere in that sequence except between a p specifier and its corresponding value P specifiers must always be on the same line as their associated values separated by at least one space The specific commands and p specifiers associated with each Dragon operation and parameter are shown in the corresponding Help messages To see the help for the operation as a whole including the command place the mouse cursor on the response panel title This information is also documented chapt1 html page 22 at 11 Jan 2006 16 21 in the Details section associated with each operation Sometimes you will want to repeat a previously entered command perhaps with a few changes Pressing the up arrow or down arrow keys allows you to sequence through the entire command history If you press up arrow in the command line Dragon displays in the command line the text of the previous command or partial command that was executed If you press
20. ds including ones which are disabled When the Status functionality is active Dragon displays a summary of what image information corresponds to the special files M B G and R This includes the image file names if the data have not been modified and the image dimensions When the History functionality is active Dragon displays a list of all the commands that have been executed in the Dragon command language discussed in the next section Even if you do not have History selected the history information will continue to accumulate Thus you can switch among the different information modes Help Status and History without losing any information In additional to the information mode radio buttons the bar between the response panel area and information display area contains a checkbox labeled Enable command line This checkbox displays or hides the command line pressing the function key lt F2 gt is equivalent The operation and use of the command line is discussed in the next section chapt1 html page 20 at 11 Jan 2006 16 21 1 4 4 Command Line Operation The Menu and Command modes of interaction look quite different However the logical structure of operations and the specifying information parameters each operation requires are almost exactly parallel in the two modes You can move easily from one mode to the other with a single key Thus you have great freedom in how much of each mode you use As you learn more about Dragon
21. e the mouse to click on the item you want or use the arrow keys to navigate to that item and hit the space bar to select it chapt1 html page 19 at 11 Jan 2006 16 21 All Dragon menu items have keyboard mnemonics shortcuts which are underined in the menu menu item label To drop down a menu press the lt Alt gt key plus the keyboard shortcut For instance to drop down the Display menu press lt Alt D gt To select a particular item from the currently displayed menu simply type the shortcut letter For instance to select Display gt Annotation type lt Alt D A gt Response panels act like standard Windows data entry forms but have a few additional characteristics Pressing the lt Enter gt key is equivalent to pressing lt Tab gt it simply causes the focus to move to the next field rather than activating the Ok button This allows you to cycle through the data fields multiple times before triggering the operation Pressing the down arrow key is equivalent to pressing lt Tab gt it causes the focus to move to the next field Pressing the up arrow key is equivalent to lt Shift Tab gt moving backwards through the fields on the form Pressing the lt F3 gt key in a field where a filename is required will bring up a file dialog so you can browse to the file You can accomplish the same thing with the mouse by clicking on the down arrow graphic at the end of the field Pressing the lt F3 gt key in a field represented by
22. erview and operation descriptions first to get a unified picture of what operations should be used for what purpose Later you can go back and study the details of each operation If you are fairly experienced with digital image processing systems you can use the Table of Contents to locate the operation you need and consult that section directly for details on how to use it The operations are described in this manual in the same sequence that Dragon presents them to you in the menus The third part of this manual consists of five chapters on more miscellaneous topics These include data transfer into and out of the system and use of Dragon s script capability which allows an ordinary text file to control the operation of Dragon without any user input The script capability is particularly useful in an educational environment for construction of demonstrations and partially automated tutorials If you are an instructor a laboratory supervisor or simply an advanced Dragon user you should read this material However it is not essential for running the basic Dragon system chapt1 html page 6 at 11 Jan 2006 16 21 The third part also includes a chapter that describes many of the file formats used in Dragon You should consult this section if you need to write a program to convert data from some other image processing system for use with Dragon Finally there is a chapter documenting several command line oriented utility programs that are distri
23. he Dragon analysis and classification operations can be limited to specified subregions of the image data These regions which are defined by a mask image can be arbitrarily complex in shape and contain numerous disconnected regions In general you can think of the mask image being overlaid on the image data Wherever the mask image is zero the image data is ignored and the resulting image will have zero value Where the mask image is not zero computation proceeds as usual Because the mask data need not have the same dimensions number of lines and pixels as the image data an arbitrary choice must be made about image data outside the mask image area In most operations pixels which are completely outside the mask image are treated as though the mask were not zero The Classify gt Recode operation uses the mask image slightly differently In this operation pixel positions where the mask image is non zero as well as any which are outside the area of the mask image will be recoded Positions where the mask image is defined and is zero are left unchanged The Utility gt Histogram operation also allows you to specify a mask image If you do specify a mask the histogram calculations include only the pixels where the corresponding mask image pixel is non zero Among its other uses this function allows you to see a histogram of the raw data values of only those pixels which were classified as members of one particular class For example to see a
24. he flexibility and speed of computers makes it possible to try different image combinations different color assignments and different noise reduction techniques The computer can also be used to search for multi dimensional patterns not visible to the human eye 1 1 2 Image Processing for Other Applications Although Dragon is intended primarily for remote sensing work it can be effectively applied to image analysis in other fields Techniques used for medical image processing for example are essentially the same as those common in remote sensing Only the vocabulary differs Dragon will be less useful in domains such as graphics arts or computer aided design Although the system does include capabilities for overlaying and combining several images it has only a few facilities for line drawing or definition of visual objects Basically Dragon can be applied in contexts where image information gathered from some outside source needs to be improved modified and combined with other image like information 1 1 3 Dragon Image Processing Capabilities This section summarizes the image processing capabilities available with Dragon It assumes that you have some familiarity with digital image processing techniques and terminology For more information about these capabilities you can consult the chapters on individual Dragon operations and the resources listed in the Bibliography When Dragon was first developed the graphics capabilities of persona
25. he most recent Display gt 3 Band operation R can be the input to most display and many analysis operations The G Green memory image contains the image which was assigned to the green color plane during the most recent Display gt 3 Band operation The B Blue memory image contains the image which was assigned to the blue color plane during the most recent Display gt 3 Band operation The special filename C does not correspond to a single memory image but rather to the collection R G and B C the C stands for the English word composite provides a convenient way to use a multi band image as a reference or background for operations such as Utility gt Cursor and Geometry gt GCP Note that it does not make any sense to specify C as the input to an analysis operation In all cases the memory images contain the true data values with no stretch applied Thus it is very fast and easy to experiment with viewing the effects of the different stretch algorithms supplied For those operations which permit you to specify a composite image C the composite image is displayed using the same stretches which were most recently used for Display gt 3 Band There may be times however when you want to change the image values for example by applying a histogram stretch Classify gt Recode provides some very powerful capabilities for doing this The results of such a stretch can be saved as a new image using File gt Save No
26. iewing the full area at reduced resolution chapt1 html page 16 at 11 Jan 2006 16 21 Another useful image data conversion program also supplied with Dragon is TIF2DRAG As its name implies TIF2DRAG can import data from the popular TIFF format produced by most image scanners In addition however TIF2DRAG can import georeferenced data from Geotiff image files Geotiff was created under the guidance of SPOT corporation and has now been adopted by many suppliers of remote sensing data 1 4 The Dragon User Interface The term user interface refers to all aspects of an interactive computer program that involve the two way communication between the program and the user Unfortunately users vary in their prior experience knowledge and ability Thus it is difficult to design a single interface suitable for all users 1 4 1 Dragon Interface Components Interfaces that offer multiple windows on the screen simultaneously such as Microsoft Windows variants Motif Gnome and KDE provide great flexibility for the user Menus can be displayed in one window images can be displayed in other windows messages and text reports can be shown in transient windows which disappear when the user dismisses them Current versions of Dragon take advantage of this flexibility providing a modern fast and flexible style of interaction The Dragon interface consists of the following components The Dragon menu client This is a window which presents a set of me
27. iewport size and displayed After you zoom in or out the viewport disables the three menu items listed above and enables the Restore option Thus you cannot do multiple successive zooms If you enlarge the image to an arbitrary factor and want to zoom in further you need to restore the image to normal resolution first and then re execute the Enlarge option using a different magnification factor Choose the Restore menu item to redisplay the image at full resolution The viewports provide facilities for printing the current image saving it to a file or copying all or part of the image to the clipboard All these capabilities are accessible through the File menu on the viewport To print the currently displayed image choose the viewport File gt Print menu item Dragon will display a standard Windows print dialog allowing you to select a printer where the image data should be sent Obviously your printer must have color capabilities if you want to correctly represent a color image Almost any printer will do a reasonably good job with a gray scale image To save the current image in TIFF format a format that can be imported into most graphics and word processing programs choose File gt Capture The viewport will display a file selection dialog so that you can browse to the location where you want to save the image and enter a filename When you click on the Ok button on the file dialog the viewport will convert the image contents to TIFF
28. image data is and where it came from For example you might call a file holding aerial photography data from Bangkok BANGKOKPHOTO IMG One common type of image data that you will use with Dragon will be satellite image data gathered with scanning radiometers such as the Landsat TM instrument These sensors usually measure reflected radiation in several different wavelengths often called bands or in some books and image processing systems channels Thus a complete set of satellite data for a particular scene will actually consist of several bands all acquired simultaneously Such data is called multispectral Multispectral data is useful because some kinds of ground cover reflect very little radiation in some wavelengths and a great deal in others Thus a particular ground cover type can be identified by its pattern of radiation levels across different bands its spectral signature In each band of a multispectral scene a particular pixel identified by a specific set of image coordinates represents the same location on the ground Because of this property all the bands of a multispectral scene are said to be registered Registration is an important consideration in digital image processing It normally does not make sense to combine two images if they are not registered since you may be combining data from two different locations Images of the same geographic area acquired at different times usually will not be registered It is possible to
29. iples techniques and terminology As an educational tool Dragon is intended to be used along with but not to replace a textbook on remote sensing image processing The description of each individual operation explains briefly what the operation does but it assumes you are familiar with the underlying concepts and assumptions If you need further information on basic image analysis issues we recommend that you consult references in the Bibliography for more in depth treatment chapt1 html page 5 at 11 Jan 2006 16 21 The manual does not assume you have had any previous hands on experience with a digital image processing system However it does require that you have a basic understanding of how to use your computer and your operating system You should know for example How to start up the computer and the operating system How to use the mouse How to insert remove and handle CDROMs What a file is how to find out what files you have available how to name rename copy and delete files How to run programs What subdirectories and paths are and how you use them You do not need to know anything about programming or programming languages to use Dragon Once again the Bibliography can provide you with resources if some of the topics above are unfamiliar to you Manual Organization This manual is organized in three general parts First there is this introductory chapter which provides an overview of Dragon and covers a number of i
30. l computers were severely limited Currently available graphics hardware allows Dragon to provide very high quality image display In general Dragon can display images up to 1024 x 1024 pixels in as many 16 million colors Much larger images can be viewed and processed by subsampling them to the required size The FCONVERT and TIF2DRAG utilities provide an automatic subsampling and data extraction capability Dragon has capabilities for displaying single band images in color or gray scale form It also includes three band color composite and image overlay capabilities Dragon provides facilities for adding titles or labels to screen images and for displaying legends on classified images The user can explicitly control contrast stretching and color assignment or allow Dragon to handle these processes automatically Most common enhancement operations are available in Dragon including band sums ratios and differences edge enhancement smoothing and arbitrary 3x3 filters A few more unusual enhancement capabilities are also provided symmetric differencing relaxation and masking The results of each enhancement operation remain available so that multi step computations such as vegetation indices can be accomplished efficiently Images created by any Dragon operation or imported from outside sources can also serve as input to enhancement processes chapt1 html page 3 at 11 Jan 2006 16 21 Dragon supports density slicing supervised classification u
31. les have the extension SPT and looks for this script in the default data directory since you did not specify any drive or path Dragon continues executing commands in this script until it reaches the end of the file then it returns you to normal Command mode Note You can also use the keyword RUN as an equivalent to for example RUN MYCLASS You can also run a script using the Run menu item under the Script submenu of File Scripts can be used for many purposes to automate a series of operations that are performed frequently to create packaged command sequences for limiting the typing required from novice users and to create demonstrations and interactive tutorials There are three limitations of scripts of which you should be aware First you cannot nest scripts That is you cannot use the at sign inside a script to access another script Second all commands and p specifiers but not necessarily parameter values in the script file must be in upper case capital letters to permit Dragon to recognize the commands Finally there are a few operations in Dragon which are so interactive that it would be meaningless to execute them in script mode These operations cannot be included in a script file chapt1 html page 23 at 11 Jan 2006 16 21 1 4 6 Interacting with the Viewports As discussed earlier in this chapter Dragon provides two special windows called viewports which are used to display images Viewports have their own me
32. line profile and area histogram displays in the Geometry gt Measure operation These output data files allow you to do statistical or graphical analyses on image data gathered from Dragon using spreadsheet statistics data base or presentation graphics software The file format for the output data file is a generic comma delimited form that is intended to be easy to import into other packages There are three types of files that Dragon uses or creates as part of the process of generating coefficients for geometric correction or registration The most important are coefficient files which have the standard file extension COF Coefficient files are used to record the regression coefficients calculated by Geometry gt Calculate They serve as a primary input to the Geometry gt Register operation which actually performs the geometric correction registration process Ground control point files with the standard extension GCP record coordinates and user defined labels for ground control points GCP files can hold either image or map coordinates They are created as an output of the Geometry gt GCP operation and serve as input to Geometry gt Calculate chapt1 html page 12 at 11 Jan 2006 16 21 Finally Geometry gt Calculate creates a report file that records the details of the regression process This report file has the standard extension OUT Dragon also creates a number of kinds of files during processing In general the detailed structure
33. lows you to browse through the files on your hard drives in order to find and select your desired file 1 3 8 3 Special Filenames and the STATUS Window Whenever Dragon permits you to specify the name of an image file to read you are being asked which data the software should operate on Frequently that data is stored in a file on your hard disk or on your network However Dragon also permits you to operate on data already in memory Dragon provides several memory images which you can use as input in some operations You tell Dragon to use one of these as the source for your operations through special filenames A special file name is a sequence of characters which would be illegal as a real file name The most important ones are listed below The M the M stands for the English word main memory image contains the results of the most recent image analysis operation This means that all Enhance operations and all Classification and Geometry operations which produce an image result place that result into M Because M can be used as the or an input to most of these operations it is very easy and fast in Dragon to chain a sequence of operations on the same data In addition to the analysis operations the Display gt 1 Band Display gt Gray and Display gt Overlay operations when reading from a disk file also load that file into M The R Red memory image contains the image which was assigned to the red color plane during t
34. messages for whatever field is currently under the mouse cursor Press lt F6 gt to switch the multifunction text area in the user interface so that it displays the current system status information Press lt F7 gt to switch the multifunction text area in the user interface so that it displays history of recent commands and messages e Press lt F10 gt or lt Esc gt to cancel the current operation and remove the current response panel from view These key sequences are also used to cancel and dismiss a sub panel and return the value in the controlling field to its default Note that if you select a new operation from the menu while a response panel is displayed this effectively cancels the previous operation as well chapt1 html page 25 at 11 Jan 2006 16 21 All control keys those that start with lt Ctrl gt in the text are entered by pressing down the key labelled lt Ctrl gt and the corresponding letter key simultaneously 1 5 2 Picking Points on Images There are several Dragon operations where you must move a graphics cursor around in the viewport These include training area definition coordinate display color scheme assignment and most Geometry operations There are two ways you can control the movement of the cursor that represents your current position The easiest way is to use a mouse Dragon can use almost any mouse or trackball for cursor movement and the mouse can be used interchangeably with the keyboard Drag
35. mportant preliminary topics In particular this chapter describes some important operating concepts that you must understand to use Dragon effectively It also discusses in detail the various ways in which you interact with Dragon to perform image processing tasks These initial topics are essential Regardless of your level of experience with computers and image processing you should read this chapter first The second part of the manual consists of six chapters that describe in detail all the operations available in Dragon and how they are used The six chapters correspond to the six main functional divisions in Dragon display operations enhancement operations classification operations geometry operations utility operations and file handling operations Each chapter begins with a general overview that summarizes the capabilities within that functional division This is followed by separate sections for each operation These individual sections describe what the operation does and make suggestions for its most effective use If you are accessing the manual via the Manual Reader application these chapters also provide access to a detailed table of all options and possible choices involved in using the operation as discussed above You may use this second part of the manual in various ways depending on your experience with digital image processing techniques and systems If you are relatively inexperienced you should probably read the chapter ov
36. n memory image always holds the results of the most recent computation This is a central concept in the organization of Dragon The main memory image is very convenient because it lets you chain together a series of operations without having to write intermediate results out into files on your disk Suppose for example you wanted to add together two image bands and then subtract a third from the result You would choose the operation for adding image bands and tell Dragon what image files held the data Dragon would read the first set of data into the main memory image then read and add successive lines from the second set of data The result of the addition would be left in that memory image Next you would choose the operation for subtracting one image from another This time when Dragon asked you what files held your data you would select the current image in memory referred to by the special chapt1 html page 9 at 11 Jan 2006 16 21 filename M for the first set of data There would be no need to save the results of the addition in an image file and then read that data back into memory for the subtraction Memory images make the sequence of operations quite efficient Note Earlier versions of Dragon actually maintained a particular chunk of computer memory for use as the main memory image In the current version of Dragon the notion of the main memory image should not be assumed to be a literal description of the system However from
37. n via the normal resources of your computer usually either hard disk floppy disks or CDROMs Satellite image data is becoming available in on CDROM form in many areas of the world including Australia Japan and the U S A Furthermore drives that can write CDROMS are quite affordable so that an organization can easily create its own data CDs A local area network also provides a convenient way to transfer large data files between computers The Tools Libraries are collections of programs available from Goldin Rudahl Systems which permit you to import image data in some of the various formats supplied by data vendors Both SPOT and TM data are available in these formats in many areas of the world and other sensor data are becoming available gradually These utilities no longer support tape drives Conversion programs are supplied to convert data files from other systems into and out of Dragon image file format One of these programs called FCONVERT described briefly in the chapters on Getting Data In and Out of Dragon and File Formats can take any image file that holds binary uncompressed 8 bit image data remove its header information if any and add a Dragon header This conversion program also allows you to take only a subset of the data in the input file either by specifying spatial limits or by taking every second third etc pixel Thus you can reduce a large scene to a size that Dragon can handle either by focusing on a subarea or by v
38. nsity and species rock and soil types water temperature and turbidity settlement location and intensity and many other important physical and social variables Remote sensing makes it possible to view and evaluate conditions in a relatively large spatial area at a relatively low cost compared to ground surveys Cameras and scanning radiometers measure the levels of radiation visible light or infrared distributed over some area of interest The data gathered by these devices can be maintained and presented in either digital or visual form In digital form the measurements are represented by a set of numeric values one number per resolution element or pixel the smallest area from which a measure of radiation can be obtained The same measurements however can also be considered as a visual image An image is a two dimensional picture of sensed radiation levels positions on the image correspond more or less to positions on the earth and the brightness of the image at any position is proportional to the amount of radiation measured at that point A visual image is the primary representation provided by a camera For traditional cameras that use photographic film special devices called scanners or frame grabbers are necessary to transform a photograph into digital form For data gathered by digital cameras or aerial or space based radiometers the digital form is usually primary A variety of computer based devices can be used to turn this
39. nu bars and some specialized functionality which is discussed in this section Most operations in Dragon finish by displaying an image which holds the results of the operation In many cases you can decide whether the results should be shown in Viewport 0 or Viewport 1 Dragon will normally size the viewport to show most or all of the image data However you can manually resize the viewport to make it smaller In this case scrollbars will appear which will allow you to view the entire image contents The Zoom menu allows you to control the degree of magnification of the image There are three items on this menu which are initially enabled when an image is displayed Magnify 3x Enlarge Overview The first two items enlarge the image so that you can see more detail To do a 3x zoom of the image select the Magnify 3x item then use the mouse to select the location on the image that you want to be in the center of the zoomed image To zoom to an arbitrary expansion factor up to 10x select Enlarge Dragon displays a dialog for you to enter the desired zoom factor After typing a number between 1 0 and 10 0 and clicking the OK button click on the image to select the center of the zoom area The third item reduces the image until it fits in the current size of the viewport In contrast to the previous two menu options Overview does not require any interaction As soon as you select the menu item the image will be shrunk to fit the v
40. nus for selecting operations within Dragon When a menu item is selected typically the menu client will display a data entry form called in Dragon terminology a response panel where you can supply the parameters necessary to the operation The menu client also provides a window for displaying help image status information or command history an optional command line and several status areas Viewports Button Panels Query Dialogs chapt1 html page 17 at 11 Jan 2006 16 21 Report Windows All images are displayed in special Viewport windows Dragon provides two viewports labeled Viewport 0 and Viewport 1 Most image processing operations allow you to select which viewport to use for displaying the results Viewports have their own menus which control image specific operations such as zooming and printing images Some of the interactive operations in Dragon such as Classify gt Training display a floating panel of push buttons which can be used to invoke particular actions The buttons on these panels are enabled appropriately depending on the state of the interaction These buttons always have function key equivalents to invoke their functionality Some of the interactive operations in Dragon also display simple query dialogs For instance if you click on the New Class button during Classify gt Training Dragon will display a dialog where you can enter or select the next class to train A number of
41. on does expect that your mouse will have at least two buttons referred to in this manual as the left and right mouse buttons Instead of using a mouse you can use the arrow keys available on the keyboard of most personal computers There are usually four arrow keys pointing up down left and right Each time you press an arrow key the cursor will move in the corresponding direction Once you have the mouse in the desired position you can select a point by clicking the left mouse button or by pressing the lt Ins gt Key on the keypad Copyright Global Software Institute and KMUTT
42. owever experienced users may get impatient if they must go through prompts in order to accomplish an operation For these users Dragon provides the Command mode In Command mode the program does not prompt for specific information You indicate exactly what you want by typing in a command that identifies an image processing operation plus command parameters that further specify the action the source of data the color scheme to be used etc In addition to the Menu and Command modes you can also use Dragon in Script mode Script files hold Dragon commands in exactly the same format you would use in Command mode 1 4 3 A Look at Dragon s Menu System Most people who have used a computer menu system will have no difficulty using Dragon s menu system The usual keys the cursor keys tab keys lt Esc gt and lt Enter gt and the usual mouse actions behave as you would expect The Dragon menu can be presented in a variety of languages other than English You can change the language used by accessing File gt Preferences gt Language When Dragon is configured for a language other than English all menus prompts messages and help will be displayed using that language in the appropriate character set Dragon has menus which are lists of items to select and response panels which are data entry forms to fill out Dragon menus work like those in any other Windows application Click on the menu to drop it down and display its items Us
43. perform a mathematical transformation on one image to register it to another chapt1 html page 7 at 11 Jan 2006 16 21 Note In some image processing systems data from all the bands of one scene are stored together in the same file This can result in very large files In Dragon each band of a scene is stored in a separate image file You must explicitly decide which bands to include or exclude in any operation Since you frequently want to process several bands of the same scene together it is important to know not only which scene but also which band the data in a file represents We recommend that you use a standard method for naming your image files such as reserving the last character in the file name for the band number For files that represent the same scene all other characters in the name would be the same Thus BANGKOK1 IMG BANGKOK2 IMG and BANGKOK4 IMG would be appropriate names for three bands of a multispectral image of Bangkok 1 3 2 Image Header Information In addition to the data values for each pixel every Dragon image file contains a block of identifying information called the header The information in this header is used to keep track of where image files came from what they represent and what processing they have received The different items of information stored in the image file header are called header fields Dragon provides you with capabilities for examining header fields and for changing many of them See
44. s Local area networks provide a facility for high speed communication between numerous different computers all located fairly close together hence the term local area Different local area networks or LAN s as they are commonly called provide different services or capabilities A LAN is almost always implemented in coordination with the operating system of the local computer so that the services provided are generally both extensions of and limited by the operating system itself Although a LAN may interconnect several even dozens of different computers the user is generally concerned with only two of these computers the one he she is using the local computer or workstation and one other which is providing the LAN services being used the server It is chapt1 html page 15 at 11 Jan 2006 16 21 generally not necessary for the user to know which actual computer is the server although on sophisticated LANs there may be several servers to choose from If you have any questions about your LAN configuration or capabilities contact your local Network Administrator a human being for information Among all the services a modern LAN can provide Dragon uses only one the file server This capability permits Dragon to use files both Dragon system files and data files which are located on the network server rather than on the hard disk of the local computer or workstation In this way the network has to maintain and store only one copy
45. s in the processing sequence If you try to select a point on the image when the viewport is not accepting points the viewport will beep You should note that some of the interactive operations such as training and vector definition will not accept points until the button panel and any other subsidiary controls are visible This sometimes takes a few seconds 1 5 Commands Used Throughout Dragon There are a few commands or control keys that can be used in all operations or sub menus within Dragon Some of these commands have been discussed before in other contexts but all are included here for for reference 1 5 1 Commands for Operation Control Several control key sequences are used for special purposes when you have selected an operation and are entering parameter values These control sequences are effective in either Menu or Command mode e Press lt F1 gt or lt Ctrl E gt to begin execution of the current operation Typing in Command mode has the same effect These key sequences are also used to accept the current values and dismiss a sub panel Press lt F2 gt or lt Ctrl N gt to switch from Menu to Command mode or vice versa Press lt F3 gt or click on the downward pointing triangle in a response panel field to get a list of possible values for that field or to bring up a file selection dialog for filename fields Press lt F4 gt to switch the multifunction text area in the user interface so that it displays Help
46. s selected in the Classify gt Training operations Polygon files can have any file name but must have the extension PLY Another kind of file used by Dragon is a script file A script file is a text file of Dragon commands created with any word processor or editor Dragon s script capability makes it possible to execute almost any series of commands automatically without any user interaction There are a few rules that must be followed but for the most part commands can be included in a script file in the same format as if you typed them on the Dragon command line See the section below on Dragon User Interface Script files can have any name but must have the extension SPT Dragon vector files which have the extension VEC are used to capture the coordinates and attributes of lines and polygons created in Geometry gt Vector The captured data can be exported to other software packages which use vector data or they can be read by Geometry gt Vector to become the basis for creating additional vectors or to be transformed into a raster data layer Recent Dragon versions have a new file type called a recoding table file These files may be used in combination with the Classify gt Recode operation to provide an arbitrary remapping of image data values Refer to the chapter on File formats for details Another new file type is the measurement data file Measurement data files are used to capture in detail the data which are displayed by the
47. sing boxcar parallelepiped minimum distance to mean and maximum likelihood algorithms and unsupervised clustering Training samples are selected interactively and can be saved examined combined and modified Training area boundaries can also be saved and then applied to a new image This allows identical areas to be used in two separate classifications e g in multitemporal studies The resulting image can be modified by combining or recoding classes Dragon provides control over colors assigned to classes Classified images can be visually overlaid on the original image or combined with the original using the masking option to assist in the interpretation of class contents Dragon also includes facilities for geometric correction and registration and for point line and polygon operations The geometric correction operations consist of interactive ground control point selection calculation of image transformation equations and resampling of the image Point line and polygon operations include provisions for creating linear feature overlays for extracting polygonal subimages cookie cutter operations and for measuring linear features Finally Dragon offers a variety of utility functions including image subsetting histograms scatterplots display and modification of identifying information in image file headers and saving of images A variety of stand alone programs are available for use with Dragon These include programs for ex
48. t every operation or image file name field will accept every special filename Generally the limitations are reasonable or obvious however the Help message for each field tells you which ones are permitted Of course you also cannot specify a name of a special file if the corresponding memory image has no image loaded into it To help you to remember which images are loaded Dragon provides a Status display listing the memory files as well as other information To see the Status window press lt F6 gt or click on Status radio button with your mouse The Status window when it is visible replaces the Help chapt1 html page 14 at 11 Jan 2006 16 21 display You can return to the Help display by pressing lt F4 gt or selecting the Help radio button How Dragon Finds a File There are two types of files which Dragon needs to be able to locate Dragon system files a category which includes the executables help files configuration files and various other kinds of files Data files including all image script signature vector polygon and registration files plus most color files The system files are almost never specified by name during normal use the file names are built into Dragon In order for Dragon to function properly these files must all be in the currently logged drive and directory while Dragon is executing If you do need to access or name one of the system files you must include a path specifier consisting of A Dr
49. te or use files in Dragon we strongly recommend that you avoid using special characters other than underscore or dash in your node names and that you keep node names to 32 characters or fewer You should never create files for use with Dragon whose node names include embedded blanks If you need to specify a file or path which does include embedded blanks you may need to enclose the entire name in quotation marks The extension is the final part All of the standard extensions used in Dragon are limited to three characters but this is not a requirement The extension provides some additional identification of the particular file However by custom the extension is used to distinguish particular types of files For example as discussed previously in this section the file extensions IMG CLF PLY VEC and SPT among others all have special meanings to Dragon 1 3 8 2 Selecting a File by Name There are many times while using Dragon when the user must specify a filename to Dragon For almost all operations the Dragon software already knows the drive path and extension portions of the name Thus you only need to enter the node name portion of the filename You may if you wish provide the full drive path nodename form in order to access files which would not otherwise be available Usually you do not need to specify the file extension chapt1 html page 13 at 11 Jan 2006 16 21 As discussed below the Dragon menu system also al
50. ted with the operation with their meanings defaults and the Dragon command language code parameter specifier for each one If the topic displayed in the Description pane does not relate to a specific Dragon operation the Details tab will be disabled When the Details pane is displayed the Previous Topic and Next Topic buttons are disabled You must return to one of the other panes to select a new topic The Manual Reader can be accessed from inside Dragon by choosing Help gt User Manual If the Manual Reader is not already visible it will be activated Then if Dragon is currently displaying the data entry screen response panel for a particular Dragon operation the Manual Reader will immediately display the Description pane for that operation Otherwise the Manual Reader will simply display the table of contents tree This manual is designed to be accessed via the Manual Reader This is the only way you can gain access in a context sensitive manner to the detailed parameter information for each operation However the manual is actually a set of HTML files and it can be read using a standard Web browser such as Netscape or Internet explorer To access the document in this way point your browser to the file doc index html within the Dragon system directory This will bring up a simple list of links to each chapter Assumptions about the Reader This manual assumes that you the reader know something about digital image processing princ
51. tion Histogram table of frequencies counting how many pixels there are in the image that have each possible value Special Fields Namestoreach Labels for classes that have been identified in the image class Georeferencing Fields that define the relationship of the image coordinates to an external information coordinate system Calibration Fields that define a mapping between image data values which range from information 0 to 255 or 0 to 65 000 to some external measured quantity such as temperature or elevation Dragon recalculates image statistics after any operation that could change image values and generally tries to maintain the header information in the computer memory in a correct state Dragon uses the identifying fields in the header for checking logical consistency in multi band operations and the statistical fields for computing automatic contrast stretch parameters density slicing boundaries etc 1 3 3 Image Memory and the Main Memory Image Dragon can only operate on data available in the computer s random access memory RAM Image data are stored in image files when they are not being used Therefore the data must be read from the disk into memory in order to be displayed or manipulated Dragon s operation depends on the concept of a main memory image All operations on images are considered to take place in the main memory image area and all results are left in the main memory image Consequently the mai
52. using Dragon A newsletter called DracoNews is published on an irregular schedule to keep users informed about new releases and other events of interest chapt1 html page 4 at 11 Jan 2006 16 21 The ManReader Application Dragon includes an application specialized for reading the Dragon User Manual This application called the Manual Reader is an enhanced HTML browser that knows about the structure of the Dragon documentation The Manual Reader is used to provide context sensitive operation specific help within Dragon However it can also be used in a stand alone mode to browse the manual as a whole You can run the Manual Reader either from the computer s Start menu Start gt Dragon gt User Manual from the command line or from within Dragon To run the Manual Reader from the command line switch to the Dragon system directory and type ManReader The Manual Reader has three tabbed panes The leftmost tab labeled Contents displays a table of contents in a tree structured form When you select a topic from the tree the center tab labeled Description comes to the front showing the text of the currently selected topic Buttons at the bottom of the application allow you to navigate to the next or previous topic in the document The third tab labeled Details is enabled only for sections of the manual that describe specific Dragon operations In these cases clicking on Details will display a table showing all the parameters associa
53. y operations menu while 1BA is the command for the single band color display operation Note In current version of Dragon Dragon unlike earlier versions of Dragon you must include the menu command in every command string even if successive commands belong to the same primary menu In earlier versions of Dragon you could execute D 1BA and then when that completes specify the next command simply as GRA without the D prefix This will not work in the current version of Dragon you must enter a fully qualified command each time Parameter specifiers also called p specifiers are codes that identify parameters All p specifiers begin with a dash followed by one or more letters or numbers For example F Image File parameter UBP User defined Upper Break Point parameter The p specifier code name is related in a more or less direct way to the name of the parameter as expressed in the response panel prompt string Similar parameters used with different operations have the same or similar specifiers to minimize confusion chapt1 html page 21 at 11 Jan 2006 16 21 Parameter Values are numbers or strings that indicate your selected value for an operation parameter The permissible values for each parameter are the same in Command mode as in Menu mode In Command mode you simply type the parameter value immediately after the corresponding p specifier on the command line with at least one space between them e g F BANGKOK2 If
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