Inner and relative orientations of digital images can be automated, 
i.e., by a programmed approximate positioning on the required 
points, followed by accurate image matching. Absolute orientation 
cannot be fully automated if the external orientations are not a 
priori known. On a master image, a small window should first be 
centered on the given control points manually. Then these image 
windows serve as the targets for automatic matching with the 
corresponding segments on overlapping images. 
After the relative orientation is accomplished, the stereo image 
should be y-parallax free. To this end, the stereo-pair of digital 
images can be resampled into the epipolar geometry or into the 
geometry of strictly vertical images at the same scale. Resampling, 
however, causes loss of image quality and it thus reduces the 
semantic content. 
An alternative to resampling is to modify the addresses of one 
image, i.e., to correct for the y- parallaxes before the display. 
4.5 Integration 
At present, any new photogrammetric system should permit easy 
integration into a larger system. If care is taken about the 
compatibility of the components, procedures, quality control and 
support, both system types are suitable for integration. 
Analytical systems employ more mechanical and optical parts than 
digital systems, an thus require more AD and DA interfaces or more 
input/output devices. 
In hybrid systems, the mixed processing and display of graphs and 
images require more hardware and support than in analytical or 
digital systems. 
Digital systems are very flexible and allow easy integration in the 
local area networks of different complexities and architectures. 
Integration, however, implies optimization within the larger system. 
The actual problems of digital systems concern the storage capacity, 
speed of communication, processing and display, and the image 
quality together with the window size. 
5. PRODUCTION-SPECIFIC FEATURES 
The specific properties of the analytical and digital techniques and 
systems can be studied and compared separately for each of the four 
main production lines and their main stages. 
5.1 Control network densification 
For aerial triangulation (at), both system types can be versatile, 
highly flexible, high performing, and can be easily operated. The 
geometric computations and quality control are similar.