Detailed Contents
1. Introduction
2. Starting DigImage
3. Basic Operation
4. Sample Session
5. Command Files
6. Movies
7. Coordinate Systems
8. Warnings, Errors and Crashes
9. Utilities
10. Macros
11. Other Considerations
12. Updates
Appendix A: Menus
Index
DigImage utilises a hierarchy of menus to provide access to the majority of its facilities. Once selected, a menu option will either provide access to a secondary menu, produce a sequence of prompts requiring user input, or immediately perform some operation. The various user input options are detailed below.
To enter a child menu or execute a menu option, simply press the key associated with that menu option. The key is not case sensitive, nor does it require that <return> is pressed. Execution will not proceed past the menu until a valid key is pressed. The <space> key may be used to toggle the status panel, at the top left of the display, on and off. The main menu entries are listed below along with a brief description of the associated branches:
| Menu item | Description |
| C: Contours and Edges | Accesses the CONTOURS program module which provides basic manipulations centred around iso-intensity contours. |
| D: Plots & Screen Dumps | Accesses the PLOTSCRN program module which provides interactive and file oriented plotting and image manipulation facilities, plus the production of hard copy. |
| E: Enhance image | Accesses the ENHANCE program module which provides a variety of techniques for enhancing the contents of an image, correcting for irregularities in background illumination etc. |
| F: Filter | Present in all program modules. Provides basic convolution, morphological, interlace and Fourier domain filters. |
| G: Grab/Display | Present in all program modules. In addition to providing an extensive array of image acquisition and display options, basic pixel-by-pixel image manipulations are also provided. |
| I Index of facilities | Present in all program modules. This option access the index facility which provides a convenient method for locating a desired feature. The option is equivalent to the <alt><f1> key sequence described in section 1.2 |
| K: Save/Restore Buffer | Present in all program modules. This option accesses a menu supplying methods of saving and reading images or sections of images to/from the hard or floppy disk. |
| L: Length scales, fractals etc. | Accesses the LENGSCAL program module which provides a number of methods for analysing the length scales contained within an image or pair of images. Included in these analyses are fractal dimensions, cross correlations, and a simple form of particle image velocimetry. |
| M: Miscellaneous tools | Starts the MISCELL program which contains a variety of tools such as font and output look up table definition. |
| P: Coordinate System Mapping | Present in all program modules. This option accesses the coordinate transformation features of DigImage. |
| Q Exit DigImage | Exit DigImage and returns to MS-DOS. |
| S: Spatial FFT | Accesses the SFFT program module which provides a simple range of manipulations and analyses based on a two-dimensional spatial fast Fourier transform. |
| T: Time Series | Accesses the TIMESERI program module which provides a number of options for analysing or averaging a time series. |
| U: Particle Tracking | Accesses the TRK2DPAR (and TRK2DRUN) program module which provides the extensive particle tracking abilities within DigImage. |
| V: Video Tape Recorder Control | Present in all program modules, this option allows precise, comprehensive control of the video recorder. |
| Z: Take Input From File | Present in all program modules, this option may be used to start command files and access a number of other related features. |
To avoid constantly changing menus during interactive operation, DigImage also provides a range of function key and other short cuts for commonly required features. These function key operations may be accessed from most but not all menus. A summary template may be accessed using <ctrl><f1>, with more detailed help information being provided by <shift><f1>. Here is a brief run down on the available operations.
Place at Top, Bottom or Nowhere ?
{TBN}->
Here the valid responses are <T>, <B> or <N>. Execution will not proceed until a valid response has been made. As with menus, simply press the desired key (no <return> required). Pressing <return> by itself (or alternative the left mouse button, if a mouse is fitted) will always select the first item on the list (i.e. <T> in this case). Frequently DigImage requires a binary choice such as
Use compaction ?
{YN}->
<return> may be used to select the first choice, and <space> (or the right mouse button, if a mouse is fitted) the second. Note that you may still use the specified letters, i.e. <Y> and <N>. If there are more than two options then <space> will have no effect.
Typed input in DigImage may take one of four forms: alphanumeric strings, integer values, floating point values and time specifications. No type checking is performed for alphanumeric strings, integers must have a zero fractional part (although the value may be entered as a floating point value), and floating point values may use any standard Fortran format. Times may be specified in a number of formats, viz.
minutes:seconds
Both the minutes and seconds may be signed floating
point values. The sign of the minutes sub-field has priority.
See <shift><f1>
for examples.
| Entry | Description |
| hours:minutes:seconds | Time in hours, minutes and seconds. Note that all the component parts may be floating point values and both may have a sign - see <shift><f1> help for examples. |
| minutes:seconds | Time in minutes and seconds. Note that both the minutes and seconds parts may be floating point values and both may have a sign - see <shift><f1> help for examples. The time is converted to seconds by 60*minutes + Sign(minutes)*Sign(seconds)*seconds. |
| minutes: | Equivalent to minutes:0. The minutes may be a floating point value. |
| :seconds | Time in seconds. May be floating point value. |
| seconds | Time in seconds. May be floating point value. |
| ::fields | Time specified in video fields. Note that there are two video fields in a complete frame. For PAL systems, there are 50 fields per second, while with North American NTSC there are 60 fields per second. |
In some circumstances DigImage may provide a default value which may be edited or overwritten, but more normally there is no default. Basic editing and recall of previous data are possible when entering any of these four data types. This may be achieved using the following keys:
| Key sequence | Description |
| <> | Move the cursor left by one space. |
| <> | Move the cursor right by one space. |
| <home> | Move to first character of entry. |
| <end> | Move to right of last character of entry. |
| <backspace> | Delete the character to the left of the cursor and move remainder of entry left. |
| <delete> | Delete the character under the cursor and move the remainder of entry left. |
| <insert> | Insert a space under the cursor and move the remainder of the entry right. |
| <> | Bring back previous entry from history list. Repeated presses of <> moves back through the history list. |
| <> | Bring back next entry from history list. This moves in the opposite direction to <> through the history list. |
| <escape> | Cancel current menu option and return to parent menu. |
| <f1> | Display help on current activity. Refer to section 1.2 |
| <shift><f1> | Display general help. Refer to section 1.2 |
| <shift><f2> | Display history. Pressing this key while inputting values (which require an <return>) brings up a list showing values (of the current type) input previously. The input may be set to one of these values by striking the appropriate key. The <escape> key may be used to exit this facility without changing the current value. To abort the current activity and return to the previous menu a second <escape> will be required. |
| <ctrl><f11> | This function key can be used to start the current screen saver at any stage where user input is requested. Note that if the frame grabber is in active use (either acquiring images or performing ALU operations) then only the computer monitor screen saver will be used. |
| <!> | Accesses command file directives and variables. Refer to section 5.3 for further details. |
Completion of input is indicated by pressing <return>.
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