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4. APPLICATION INTEGRATION
AND MATERIAL COVERED
As already mentioned the authoring software used to develop
"Photogrammetrist v.1.0" is Aymmetrix ToolBook 1.5.3. The
object oriented structure of this software allows for the easy
design of electronic pages including buttons, hotwords, menus,
check buttons etc.
In "Photogrammetrist v.1.0” the basic concepts of
Photogrammetry are covered in 150 electronic pages. Each
electronic page consists of 50% of designs, graphics and
dynamic pictures, 10% of a set of navigation buttons, 15% for
the title of the units and subunits and 25% of text that
embodies hotwords and hypertext (Figure 5). In addition a
section with numeric exercises has been developed, where the
user can study, by clicking the button ‘Knowledge’, the
corresponding page of theory. Also by clicking the button
‘Calculator’, a simple calculator appears, which was included
in the development to help the solution of simple arithmetic
equations.
Figure 5: A typical electronic page of "Photogrammetrist v.1.0"
The seven electronic books include the following topics:
1. The Photogrammetric Procedure
Photogrammetric applications
Air survey planning
Data Collection (Figure 6)
Geometric model of Central Projection
Photogrammetric products
2. Examination of the optical ray path
Distortion due to earth curvature
Distortion due to atmospheric refraction
Distortion due to material shrinkage
3. Interior Orientation
Coordinate system of air photograph
Radial lens distortion
Displacement of principal point
Principal distance
4. Single image Photogrammetry
Object and photo coordinate systems
Scale differences of map and photograph
Factors affecting photo scale
Rectification
49
Orthophotography
Photomosaic and orthophotomap
Figure 6: Data collection and Photo scale
5. Stereoscopic vision and Parallax (Figure 4)
Natural stereovision
Stereoscope
Parallax (Figure 7)
Relative orientation
6. Orientations
Coordinate systems
Collinearity equations
Resection in space
Exterior orientation
Absolute orientation
7. Exercises (use of calculator)
The self-studying character of the program posed several
limitations. Firstly, the application should be able to run with
minimum hardware demands. This was decided to be as little
as a 386SX CPU, 2 MB RAM, SVGA monitor (640x480, 256
colours), no sound card, no networking. The problem of sound
and speech was bypassed with the use of the PC Speaker
driver, which is available free from Micrososft. The PC
Speaker allows the computer speaker to output simple but
recognisable sound and speech files (.wav files, 8 bit, 11 Khz,
mono). Secondly, the distribution of the program in floppy disks
prohibited the extensive use of images and the use of video.
The majority of figures are drawn with the simple drawing
tools, provided by ToolBook. In general, when dealing with
multimedia applications the effort to reduce the space
increases the time needed to develop the application.
Fab
SI
Figure 7: Steroscopic vision and parallax
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B6. Vienna 1996