AUTOMATION IN DIGITAL PHOTOGRAMMETRIC SYSTEMS 
Scott B. Miller 
Director of Engineering, Helava Associates, Inc., USA 
Fidel C. Paderes Jr. 
Chief Photogrammetrist, Helava Associates, Inc., USA 
A. Stewart Walker 
Product Manager Digital Photogrammetry, Leica AG, USA 
Commission II, Intercommission Working Group II/III 
KEY WORDS: Scanner, Correlation, Expert System, Edge, Image Understanding, Automated Feature Extraction, 
Digital Photogrammetry, Radiometric Mosaicking 
ABSTRACT 
The promise of digital photogrammetric systems is often couched in terms of the potential or expectation of automation. Nevertheless, 
increases in usable automation have been slow to develop. Still, there is a continuing increase in practical automation in commercial 
digital photogrammetric systems. This paper reviews the current automation in the Leica-Helava digital photogrammetric systems and 
our continuing investment to achieve the highest levels of practical automation for the near term. Automation at various levels is 
discussed in virtually all phases of digital photogrammetry. The functions discussed include scanning, GPS triangulation, automated 
point measurement, automated elevation measurement, automated vector extraction, automatic mosaicking and dodging, and several 
semi-automated operations. Real gains in productivity are evident. These developments constitute a considerable presence of practical 
and increasingly robust automation in digital photogrammetry. 
1.0 OVERVIEW algorithms are also used to assist the user in the automatic 
setting of tonal transfer curves to obtain a better digital image. 
The potential of digital photogrammetric systems has often been 
stated in terms which include tantalising references to the 2.1 Automation in Image Scanning 
potential or expectation of automation. Nevertheless, increases 
in automation have been slow to develop to fulfil the promise Automation in image processing is particularly necessary as we 
(Leberl, 1991; Dowman, 1996). There is a continuing increase begin to offer the DSW300 roll film scanner. This third 
in practical automation occurring, however, in commercial generation scanner offers automatic interior orientation, 
digital photogrammetric systems. Leica-Helava and other automatic image balancing and automatic frame advance. These 
researchers and vendors are exploring and implementing features combined with very high speed scanning (less than 4 
practical automation at all levels of the photogrammetric data minutes for 12.5 pm, 230 mm square, black and white images) 
collection process. We present here the current status of Leica- have increased considerably the productivity of feeding the 
Helava automation and discuss its impact on productivity. The digital photogrammetric pipeline. Thus digital data is increasing 
major areas of the photogrammetric process are all covered, in quality and availability at lower cost. 
including scanning, triangulation, elevation and vector 
extraction, orthophoto and mosaic production, and other related 2.2 Advances in Networking and Peripherals 
products. Worthwhile improvements in productivity are a key 
area of our developments. These developments include simple It is critical, of course, that the benefits of this rapid scanning 
things such as reducing production steps as well as very are not squandered by bottlenecks in forwarding the data to the 
complex autonomous operations. next stage in the flowline. Thanks to major advances in 
electronics and computer technology, digital photogrammetry is 
becoming much more productive than it was just a few years 
2.0 IMAGE SCANNING ago. The integration of higher speed networks and disk RAID 
systems have aided the practicality of high speed scanning and 
In digital photogrammetry today, the majority of digital drastically reduced the need for user interaction. A single 
imagery is derived from the scanning of film. Until higher scanner connected to a large disk system is able to scan 
resolution satellites and/or more efficient aerial digital cameras autonomously for many hours. The advent of higher speed and 
become available, film is expected to remain the major source density peripherals has also helped to make this practical. For 
of digital imagery. The push for higher productivity has driven example, the Digital Linear Tape devices are now capable of 20 
us to develop techniques and mechanics for autonomous and GB of storage and can be written at speeds of up to 3 MB per 
efficient film scanning. In this area, algorithms for the second. This permits a single tape to hold 200 230 mm square 
automatic detection of hot spots and vignetting have been images when scanned at 25 pm or approximately 200 images 
developed to dodge or balance images automatically. These scanned at 12.5 pm when compression is used. When one 
250 
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B2. Vienna 1996 
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