allow us to advance at the expected and required 
speed. 
The change to a new and modular concept was 
sharp and with consequences. The basic idea was to 
have a system which could be utilised in a most 
general and flexible manner, which uses as many 
hardware and software standards as possible, which 
can grow and expand as a system and which also 
allows the user to advance quickly by either 
continuously providing for new functionality, more 
processing speed and memory space and/or by 
giving the user fast access to its own tools and third 
party products. 
The concept to go for was to use a workstation 
based system, running the UNIX operating system 
with its true multi-tasking and multi-user 
capabilities, advanced programming tools, a 
powerful window system, fast and high resolution 
display system, fast access to large memory, and 
the ability to network with other systems and 
instruments. When we made our purchase decision 
in autumn 1986, workstations from Sun 
Microsystems offered all the required features at a 
reasonable price. 
Since then we have constantly expanded our 
system. As of today it consists of two fileservers 
and 9 workstations (Sun-3, Sun-4 and 
SPARCstation 1GX). Currently almost all Sun-3 
workstations are upgraded to Sun-4/SPARCstations 
in order to have a unique environment for easier 
system management and compatibility. All 
fileservers and workstations are linked via 
Ethernet. They can act individually and together as 
programming and processing platforms. 
exceeds that of an analytical plotter. Of course, 
until some of the major procedures work fully 
automatic one has to accept hybrid systems as 
intermediate solutions. As will be outlined in the 
next chapter, DIPS II contains fully digital 
capabilities with hybrid components. 
3. DIPS II components 
Figure 1 indicates the stereo image acquisition 
system, and Figure 2 the current arrangement of 
peripheral devices. It is of great importance to this 
concept that all components can easily be 
upgraded, expanded or exchanged if the situation 
requires it. 
CCD-Cameras 
• MaxVideo Boards 
(Datacube) 
• Workstation (SUN 3-E) 
w 1 
Display 
LnnJ 
яшм 
Ethernet 
Figure 1 : DIPS II general stereo image acquisition 
system 
3.1. Computer features 
DIPS II currently consists of: 
There are two workstations which will remain at 
the original Sun-3 level: A Sun-3/E equipped with 
DATACUBE boards for general image acquisition 
and preprocessing (Figure 1) and a Sun-3/110 
which is dedicated to image acquisition, 
processing, system control, data acquisition and 
data base management for the PRIME WILD S9 
analytical plotter. 
It should be noted that our system is primarily 
designed to serve for the research in and 
development of algorithms and procedures rather 
than for production. Therefore our approach is not 
limited to stereo and is not geared towards manual, 
operator driven processing. The procedure of 
“stereo”-processing is clearly related to a human 
operator making use of his ability to view the 
photogrammetric model three-dimensionally. It 
makes full sense only in an operator measurement 
mode. We feel that the full advantage of a digital 
station can only be realized if it is capable of 
executing functions which go beyond stereo 
processing and which are semi- or fully automatic. 
Digital photogrammetry will have an impact on the 
future of the discipline only if its functionality 
• 7 SPARCstation 1GX, each with 12 MB 
memory and GX graphics accelerator 
• 1 Sun-4/280 and 1 SPARCserver 490 fileserver 
with a total of 5 Gbyte of disk space 
• 1 Sun-3/110 primarily used as S9-AP support 
and with 8 MB of memory 
• 1 Sun-3/E workstation with 8 MB of memory, 
mainly used to support the DATACUBE system 
The SPARC (RlSC)-workstation architecture is 
supported by an S-bus whose peak transfer rate is 
specified as 60 MB/sec. According to our practical 
experiences, the transfer rate from memory through 
this bus to the framebuffer is about 22 512x512 8- 
bit images per second. If the image size exceeds the 
physically available memory space the data must 
be retrieved from disk reducing the transfer rate to 
below 2.4 MB/sec. This is certainly not enough for 
continuous operator-image interactions like 
panning and scrolling and it is insufficient for video 
real-time display requirements of longer image 
sequences. The former problem can be solved by 
installing a virtual memory technique, the latter 
case has never been required by us so far.