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program will usually have an initialiser and some other real-time and 
off-line parts. For example, a scanning operation needs the initial 
identification of the scanning pattern and mode of recording before the 
real-time part of the program takes action. That real-time part will 
have, besides the transformation and correction routines for addressing 
of conjugate image points, a routine for execution and control of scan- 
ning and recording. 
The design of the application programs, the choice of the con- 
figuration of their real-time, near-real-time and off-line components, 
and the organization of their interaction are conceptually and practi- 
cally the most interesting and most important facets of the overall 
software design for an analytical instrument. Once the general capabi- 
lities of an analytical instrument are determined by the choice of the 
computer and its peripherals, and by the design of the optical- 
mechanical component and the interface, the whole development of methods 
and techniques will depend entirely on the design and the performance of 
the application programs. 
3. ORIENTATION PROCEDURES 
  
The significance of analytical instruments for the development 
of procedures and techniques is probably most easily understood in 
relation to the orientation programs. The advantages derived from their 
high accuracy, speed and flexibility are almost self-evident when 
analyzing computational procedures for determination of orientation 
parameters. The choice of mathematical models is unlimited. The 
orientation parameters can be determined with rigorous adjustment pro- 
cedures. In other words, the off-line parts of orientation programs 
are as general as in off-line computational photogrammetry. The time 
needed for the determination of parameters by these off-line parts is 
negligible in comparison to the time needed for collection of data. For 
example, the execution time for the relative or absolute orientation of 
frame photography is of the order of 10 seconds (coded in Fortran). 
That is approximately two orders of magnitude faster than the time 
needed for the collection of data. 
Since the distribution and the number of points at which the 
measurements are performed (i.e. the number of observation equations) 
is not critically influencing the computation time as it did in older 
analytical instruments, the significant saving on the overall execution 
time of an orientation can be achieved by shortening the data collec- 
tion operations. For this purpose a number of techniques can be used 
that are based mainly on the possibility to position the measuring mark 
under computer control in the vicinity of chosen points (e.g. with 
speeds of 50 mm/sec). For instance, the interior orientation programs 
may allow for the choice of several distribution patterns of fiducials. 
After stating the desired pattern in the initialiser and after approxi- 
mate centering of carriages, the measuring marks are positioned auto- 
matically in the vicinity of the fiducials. This technique not only 
increases the speed of data collection but considerably diminishes the 
chances for gross errors. It also allows precise positioning, after 
the completion of interior orientation, on the points in which the 
measurement has been made, That permis an exceedingly fast and effi- 
cient inspection of the results of the orientation.