Figure 13 shows the main classes of photogrammetric instruments for 
information collection in digital form. 
: Computer supported 
  
  
  
  
& hybrid 
Stereo ——— Analytical 
Restitution L-— Al1-digital (7) 
instruments ____ Computer supported 
(digital) rectifiers 
Line rectifiers 
La Mono —— Analyticol AMPs 
Ortho-printers 
L__All-digital(?) 
Fig. 13: Classification of photogrammetric instruments (digital). 
A prerequisite for integration is compatibility of sub-systems and their 
components. This applies to the past, present and anticipated future 
systems. 
Integrating new hardware components into on-line systems introduces the 
need for additional interfaces. Moreover, in real-time systems, con- 
sideration should be given to the timing of operations and of 
correspondiong communication. 
4. Software 
For the purpose of integration, compatibility of the software structures 
and modules, and their documentation are essential. Modular structures 
permit easy implementation of changes and expansion, but they may not 
necessarily be efficient in terms of time and storage. Hence, the degree 
of modularity should be balanced against efficiency. 
Software can be classified according to the system main tasks (or 
functions), process stages, control of input and output, and interactive 
operations. 
The system main tasks can be structured as follows: 
— Operating system 
— Basic photogrammetric software 
Photogrammetric application software 
Related application software 
— Service programs 
Each of these classes can be differentiated further according to the 
process stages, control and interactive operations. 
5. Interactive capability 
The man-machine interactive capability should reflect the principles of 
human engineering. Human operators interfere in all main process stages. 
In the information collection stage, the interactive operations are 
involved in the preparation phase, feature extraction, measurement, 
supervision and verification, pre-editing and conditioning of the infor- 
mation and data. The operator’s tasks are thereby perceptual, processing 
and control. Each main process stage requires its own hardware and 
software components for interactive operation. AN and graphic terminals 
can be shared. Sub-systems for graph-image overlay in photogrammetric 
plotters have recently been introduced. 
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