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