2.3 Individual Software Tools 
For data fusion, image visualization and data integration 
several individual software tools have been developed. 
The program  VIEWPL allows image coordinate 
measurements with the graphical mouse on the PC 
screen. It displays raster images in BMP-image format. 
A very simple on-screen digitizer with additional graphical 
overlay function is realized in the module LINEPL. 
With the on-screen digitizing tool ONSCRE up to ten 
classes can be measured and saved onto disc. This is 
done with additional geolocation information and in 
standardized database format (dBase). 
The rectification program BPROTRA is based on an eight 
parameter projective approach. It is used for all required 
resampling purposes dealing with image to image 
registration in flat terrain (Albertz, Kreiling, 1980). 
The mosaicing of edited satellite images, for example 
ERS-1 radar images, will be carried out with the data 
fusion software MOSES. ; 
Image conversion software has been implemented to 
handle SUN rasterfile format and MS Windows BMP- 
formats. The functions are SUNTOBMP and BMPTOSUN. 
To immediately start the on-the-job training it is 
recommended to use also standard PC-software which is 
always present on PCs. 
For image display and painting the MS-Windows program 
PBRUSH is used. If the candidates have to edit ASCII 
textfiles or coordinate files the NOTEPAD editor is always 
sufficient. 
Very important to handle MS-DOS applications under MS- 
Windows is the PIFEDIT module. This function is not 
necessary under MS-Windows ‘95 any longer. 
3. SOFTWARE DESIGN 
Depending on institutional software requirements the 
above mentioned tools have been developed in C- 
programming language under MS-DOS and MS- 
Windows. 
3.1 MS-DOS Software 
To ensure batch ability and to be independent from any 
graphical user interface (GUI) the following modules have 
been developed in C-language: 
BPROTRA, 
MOSES, 
SUNTOBMP, 
BMPTOSUN. 
. Most of the software developers know the problems with 
memory management under MS-DOS. 
Caused by the 65 kByte border it is impossible to work 
with large image arrays stored in the main memory area. 
To avoid these complications and to work without 
additional memory DOS extenders all mentioned modules 
work line-oriented in direct access to the image files 
stored on disc. 
3.2 MS-Windows Software 
Most of the modern software tools work under graphical 
user interfaces like X11, Motif or MS-Windows. To use all 
the built-in features of MS-Windows all new software 
modules have been developed under this user interface 
programmed in C or C++ language. 
The GUI allows multiwindow application, access to 
several preinstalled device drivers and additional 
peripheral equipment. 
To enable fast image display and simple image 
coordinate measurement in images and maps at the 
same time the modules VIEWPL, LINEPL and ONSCRE 
are inplemented under MS-Windows. 
All programmes are menu-driven with file-I/O functions 
and graphical mouse support. 
The above mentioned DOS modules are called from 
these tools by system calls using program interface files 
(PIF). 
3.3 Implementation 
To show some of the training steps the detailed 
implementation of the additional software is outlined now. 
In most of the digital image processing applications the 
first steps will be the image display, the measurement of 
tiepoints in digital images and the rectification of the 
image to a given map reference. 
All these functions are covered by VIEWPL, which loads 
8-bit raster images and displays them with 256 colors or 
greyvalues. A roam function is realized to handle images 
which exceed the monitor dimensions. The measurement 
of image coordinates is carried out by the pointing device 
(mouse cursor). 
The measured coordinates and image dimensions are 
stored on ASCII files for further calculations. To compare 
original and reference image location the program can be 
started simultanously with both images at the same time. 
Input data for the program are raster images and digitized 
maps, output data sets are two text files with 
corresponding image coordinates for the following 
rectification process. 
The projective transformation is calculated with the 
programm BPROTRA, which stands for Bytewise 
PROjective TRAnsformation. 
The perspective distortions are corrected in a straight 
approach with four measured tiepoints. Without any 
adjustment this approach uses the eight transformation 
coefficients for the indirect resampling of the digital input 
image (Brandstátter, 1995). The corrected output image 
will be stored in 8-bit and also 24-bit BMP raster image 
format. 
A very important processing step is the quality control of 
the rectified image. For this task the programmes LINEPL 
and ONSCRE have been implemented. Both modules are 
able to visualize raster images on screen and to add 
graphical overlays derived from vector data sets. 
The vector information can be edited, deleted and 
updated with the pointing device. The onscreen digitizer 
ONSCRE  additonally offers functions to generate 
database interface files and a mosaic control file for the 
following mosaicing software (Wiggenhagen, 1993). With 
this tool the user can define regions of interest which will 
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B6. Vienna 1996 
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