2004 
  
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The Promise of Softcopy Photogrammetry Revisited 
F. Leberl", J.Thurgood” 
D Vexcel Imaging GmbH, 
Münzgrabenstrasse 11, A-8010 Graz, Austria 
& 
Institute for Computer Graphics and Vision, Graz University of Technology 
Inffeldgasse 16, A-8010 Graz, Austria 
Email: franz@vexcel.com 
? Vexcel Corporation, 
1690 38" Street, Boulder, Colorado 80301, USA 
Email: joe.thurgood@)vexcel.com 
Theme Session 12: Automated Object Extraction and Computer Vision Application 
KEY WORDS: Digital Aerial Camera, Softcopy Photogrammetry, Photogrammetric Paradigm, Multi-Ray Matching 
ABSTRACT 
Digital large format aerial cameras can produce as many images as a user pleases, and yet the costs of the imagery do not increase, in fact 
they decrease. This is a vast difference from traditional film-based photogrammetry where minimizing the number of film images was a 
basic tenet of the discipline, since a project's costs were directly proportional to the number of images needed to complete it. Minimizing 
costs no longer is defined by minimizing the number of images, but by minimizing the use of human labor hours. The entire economy of 
aerial imaging is changing with the transition to digital cameras and the full digital workflow. This will change the market's behavior, 
both on the side of the end-users of photogrammetrically collected data as well as on the side of photogrammetric organizations. 
More images will be created per project, mapping repeat cycles will shorten, costs per project will decrease, new data products will 
emerge and the competitive cost structure in photogrammetric organizations will come under intense pressure. 
1. INTRODUCTION 
Innovation in photogrammetry is accelerating under the influence of 
innovation in computing. It took about 25 years for the analytical 
plotter to move from its initial inception in the mid-50s to full 
acceptance in photogrammetric practice by 1980, marked by the 
ISPRS Congress in Hamburg. It took 10 years for the softcopy 
photogrammetry approach from an initial demonstration in 1990 
when the initial precision film scanners became available, to full 
acceptance by 2000, the time of the Amsterdam ISPRS Congress. 
That acceptance was caused by both the feasibility via computing 
innovations, as well as the reemergence of the orthophoto. Major 
photogrammetric functions continued to be based on film, such as 
aero-triangulation and manual stereo vector collection. By about 
2000, the time of the ISPRS Congress in Amsterdam, nearly every 
photogrammetric organization had become a user of softcopy 
photogrammetry, but only for ortho photo production. A minority 
had abandoned all film-based procedures and had converted to a 
strictly softcopy approach for all phases of photogrammetric image 
analysis, increasing the AT-throughput from perhaps 4 images per 
hour to 10. 
Only 4 years have passed since the initial announcement and 
demonstration of digital large format aerial cameras in 2000 and 
now their large-scale acceptance into photogrammetric practice at 
this time is happening. Today, numerous digital cameras are flying 
(Petrie, 2003). Only a mere 4 years after the initial announcement 
can we already see that new large format aerial cameras will no 
longer be relevant unless they produce digital imagery. 
The reason for this rapid acceptance of digital cameras is the 
promise of a fully digital workflow with benefits in economy and 
with the advent of innovative data products (Leberl & Gruber, 2003; 
Gruber et al., 2003). This transition is more fundamental than all 
previous innovations, since it will shake up the field in many ways. 
We argue that the photogrammetric field will convert to be a special 
computer application, with no trace of film left in any work flows. 
Traditional value systems based in photo scales, number of photos, 
scanning resolutions, levels of automation will go away, to be 
replaced by pixels, file sizes, archives and catalogs, the internet and 
immersive uses of 3-dimensional spatial data. 
We want to examine the current situation and visit the status of 
softcopy photogrammetry in light of the advent of large format 
digital aerial cameras, progress in computing, fully automated 
procedures for AT, DEM and orthophoto generation, and the 
emergence of new types of terrain and GIS data products. 
2. SOFTCOPY EVOLUTION 
2.1 Definition 
Digital or softcopy photogrammetry designates the use of digital 
images for photogrammetric procedures and products. The 
beginning of this new technology depended on the availability of 
digital images, and these in turn required the advent of precision 
film scanning systems. Scanning film images leaves the image 
acquisition unchanged, and the traditional rules remained applicable 
to aerial photogrammetry since its early days 100 years ago. 
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