ctronic 
Q en Ti 
oletely 
otry is 
, 1955 
10logy, 
al-time 
stem's 
e near 
sts for 
n was 
1956). 
| Scan 
active, 
howed 
inating 
till the 
ing for 
nts in 
ent of 
gy and 
> their 
stems 
cts of 
d their 
stems 
stalled 
les of 
1,200 
ractice 
Digital 
ies of 
ind in 
At the 
Zurich 
|-time 
1 host 
nents 
for general data processing and image processing functions. It is intended to develop and implement 
the photogrammetric components in order to turn the base system into a Photogrammetric Station, 
designed to perform photogrammetric data acquisition and data processing functions for a variety of 
tasks. 
This paper presents the system in its current configuration, describes the ongoing extensions 
and improvements, and addresses the R & D concept of the near future. 
2. Potential of a Digital Station 
Analog and analytical photogrammetric data processing is characterized by a great variety of 
different instruments, e.g. comparators, stereoplotters, triangulators, rectifiers, orthoprojectors and 
special application equipment for non-conventional imagery, each of them used to perform certain 
specific tasks. These instruments vary greatly with respect to design, construction, universality, 
flexibility, accuracy, usage, control, input and output. Only the Analytical Plotters feature a certain 
degree of task integration, i.e. they allow to perform different types of tasks on the same instrument. 
The Digital Station has, if fully equipped, the unique ability to perform all usually required 
photogrammetric and cartographic functions of data processing, and partly even of data acquisition. 
The Digital Station is capable of 
- Line and point mapping 
- Point positioning 
- Mass point generation 
It works in the modes 
- Operator controlled 
- Semi-automatic 
- Fully automatic 
It can process 
- Mono, stereo and multi-image arrangements 
- Terrestrial, aerial and satellite imagery 
- Different kind of imaging sensors, sensor combinations, non-imaging sensor data 
- Digitized photographs, digital scenes 
Other features include 
- Photogrammetric and cartographic editing 
- Integration of computer graphics and image processing functions, e.g. superposition of map 
and image data 
- Interface to conventional instruments for input and output 
- Products in analog and digital form (hardcopy, softcopy) 
Thus a Digital Station is more than just a Digital Plotter, it becomes a universal instrument which 
allows to perform a great variety, if not all, tasks at one single system. 
Other advantages of a digital system include 
- no high precision optical-mechanical parts required 
- robust measurement system; no wear and tear 
- no need for conventional type of instrument calibration 
- no manual image handling 
- Stable images, no deformation over time 
The basic photogrammetric functions could be used on a Digital Station in pretty much the same 
way as they are implemented on an Analytical Plotter. Beyond this the digital concept opens some 
interesting new aspects. Photometric operations, like different types of enhancements, contrast 
alterations, enlargements/reductions, coloring, etc. can be performed quickly and inexpensively. 
Like an operator on a conventional instrument never needs the whole photograph/stereomodel 
at a certain moment for processing, the complete digital image(s) do not have to be operated 
(transferred, accessed, roamed, zoomed, resampled, etc.) at the Digital Station. Even in an operator 
controlled mode it would be sufficient to provide for a low resolution overview display on a separate 
CRT (for 1024 x 1024 resolution: À complete aerial photograph of 23 x 23 cm? could be displayed at 
77