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only for a wide range of possible transformations of transfered images but 
also for their enhancement (Real, 1982). Electronic image transfer also 
eliminates the rigid constraints imposed by the optical trains on the overall 
design of analytical instruments, and allows for a flexible configuration of 
system components (e.g. the photo-stage configuration) and for easier 
implementation of techniques for real-time superposition of graphics in the 
stereo-model. 
The overall organization of software packages and the optimal design of 
application programs exploiting the best features of man-machine interaction 
are still wide open fields for research and development (Slama, 1982). Some 
unique, already developed, on-line techniques for compilation of time- 
dependent imagery, for exploitation of multi-model solutions in close-range 
photogrammetry and for processing of multi-media photography are good 
indicators of the potential of analytical. instruments for opening up new 
areas of application. 
AUTOMATION OF PROCESSES 
Some of the routines and techniques of on-line analytical photogrammetry 
which do not require the operator's intervention, such as the routine for 
automatic positioning of the measuring mark in predetermined positions or the 
editing playback technique, may be considered as automation of processes. On 
closer examination, it is evident that these simple automatic processes are 
just a consequence of a direct computer drive of positioning devices without 
the involvement of any decision making control processes or machine- 
intelligence. 
Taking in account the present status of the theory and technology in 
artificial intelligence a full automation of all the processes needed to, 
for example, extract from images all the required information for the 
establishment of digital files of a cartographic data base must be deemed 
intractable. For instance the pattern interpretation that is an integral 
part of all the processes for feature compilation is still confined within 
the boundaries of human intelligence. This is the reason that the only 
practical way to deal with planimetric features is to generate an orthophoto, 
that is, to perform a pictorial-to-pictorial conversion by automatically 
transforming the metric information and leaving the semantic information 
virtually unchanged. 
The level of machine-intelligence needed for the extraction of information 
on elevation is somewhat lower since it can be based on relatively simple 
automatic image matching techniques. Attempts at automatic generation of 
digital terrain models and digitizing of contours have been made by analog 
electronic scanner correlators and by optical scanners using digital 
correlation techniques. The goal of these devices is the measurement of 
parallaxes in an oriented model and the consequent determination of elevation 
or generation of a control signal for the positioning of stages. The image 
matching in these devices has been based by and large on cross correlation of 
two image density functions (Konecny and Pape, 1981). The cross correlation 
function has a maximum when the images are shifted the correct amount 
relative to one another. 
These devices have proven quite successful under favorable conditions. But 
they fail in cases of discontinuities (e.g. large scale images of built-up 
areas), on steep slopes, and where a correlation is possible simultaneously 
at different elevations (e.g. sparsely forested areas). These difficulties 
may be overcome with the aid of the human operator, but the processes have