DIPS II - Tùrning a Standard Computer Workstation into a 
Digital Photogrammetric Station 
A. Gruen, H.A. Beyer 
Institute of Geodesy and Photogrammetry 
Swiss Federal Institute of Technology 
ETH-H5nggerberg, CH-8093 Zurich, Switzerland 
Abstract 
This paper describes an attempt to turn a standard computer workstation into a digital 
photogrammetric station, following the concept of modular design. Hence a basic advantage is the 
flexibility and openness of the system with respect to hardware and software integration, 
development and maintenance. At the Institute of Geodesy and Photogrammetry of the ETH 
Zurich, our digital photogrammetric station, DIPS II (Digital Photogrammetric Station II), consists 
of a number of Sun Workstations (Sun-3, Sun-4, SPARCstations) linked to each other via Ethernet 
with some external off-the-shelf components for digital image acquisition and output. All 
workstations can act individually or together as programming and processing platforms. Most 
software is written in C with a few minor portions in FORTRAN 77. Of particular value is DEDIP 
(Development Environment for Digital Photogrammetry) which is written in C, uses the Sun View 
window environment, provides for data structures and user interface, and accommodates most 
newly written programs. DIPS II serves as an indispensable tool and platform for all research and 
development projects of our group in digital photogrammetry, remote sensing, machine and robot 
vision. 
1. Introduction 
The concept of a fully digital photogrammetric 
workstation is relatively new. Its importance for the 
future of photogrammetry as a discipline is 
indicated by the fact that a number of research and 
development groups have been actively pursuing 
the issue in recent years. 
In a survey paper, Helava (Helava, 1988) has 
outlined the merits of fully digital systems and 
described the status of technology with respect to 
different tasks and products. Some of the early 
developments have been referenced in Gruen, 
1989. In the meantime the interest has even 
increased and new work can be found in Cogan et 
al., 1988; Konecny et al., 1988; Lohmann et al., 
1988; Molander, McIntyre, 1989; Cruette, 1990; 
Gagnon ei al., 1990; Mori, Murai, 1990; RISM, 
1990; Sarjakos/d, 1990; TOPCON, 1990. 
In 1985, our group started with a first prototype 
system using a commercial image processing 
system as the central core. As this “turn-key image 
processing system concept” turned out to be too 
restrictive with regard to software development and 
hardware additions we changed our basic system 
philosophy soon after to the “modular” approach 
{Gruen, 1989). Modularity means openness on the 
hardware and software side; it also stands for 
flexibility and adaptability with respect to costs and 
functionality. 
Our second generation digital station DIPS II, 
which is based on an extendable number of Sun-3 
and Sun-4 workstations, linked to each other via 
Ethernet and equipped with off-the-shelf 
components for digital image acquisition and 
output, will be described in this paper. 
We will explain why the modular concept is of 
fundamental value to us. A major chapter is 
devoted to the hardware and software environment 
and the components of DIPS II. Computing times 
associated with certain algorithms will give an 
indication of the computational performance of the 
individual CPUs without the use of extra processor 
hardware. Finally, some typical applications, most 
of them performed as pilot projects, will be 
reported. 
2. From DIPS I to DIPS II: Why the change in 
concept? 
In Gruen, 1986 a description of DIPS (I) was 
given, a system which was then based on the 
commercial image processing system KONTRON 
IPS 68K. Although this system gave fast access to 
standard image processing routines, anything 
which went beyond that and was typically 
photogrammetric in nature was cumbersome to 
install or not possible at all. Being fully dependent 
on the manufacturer with respect to hardware and 
software modifications and extensions did not