A COMPARISON OF THE UTILITY AND EFFICIENCY OF DIGITAL PHOTOGRAMMETRY 
AND INDUSTRIAL THEODOLITE SYSTEMS 
Giuseppe Ganci 
Fisher Stewart Pty. Ltd 
39 Park Street 
South Melbourne 3205 AUSTRALIA 
Telephone: +61 3 9694 1200 
Facsimile: +61 3 9694 1211 
Email : ganci@sunrise.sli.unimelb.edu.au 
Mark R. Shortis 
Department of Geomatics 
The University of Melbourne 
Parkville 3052 AUSTRALIA 
Telephone: +61 3 9344 6806 
Facsimile: +61 3 9347 2916 
Email : M.Shortis@unimelb.edu.au 
ISPRS Commission V, Working Group V/3 
KEY WORDS: 
ABSTRACT 
Photogrammetry, metrology, inspection, CCD camera, close-range networks, theodolite triangulation 
This paper reports on the suitability of digital photogrammetry as a viable and effective alternative to theodolite triangulation. 
Particular attention is drawn to a case study where both methods were initially considered as appropriate measurement techniques. 
Emphasis has been placed on some of the practical aspect involved in determining which method could be ideally applied to the case 
outlined. Based on this evaluation the project was completed using the digital photogrammetric technique which emerged as the 
clear choice. Sufficient detail is given to provide the reader with some useful insight into the logistics of this type of project. The 
discussion also provides the reader with a feeling for the different features and factors inherent in each system. 
INTRODUCTION 
Theodolite triangulation has been successfully applied in a 
variety of metrology applications for a significant period of 
time. The use of theodolites for angular intersection can be 
traced back to as early as 1944 (Shortis and Fraser 1991). The 
principles of such systems is well known (Allan, 1988) and they 
have gained widespread acceptance for industrial measurement 
applications (Roberts and Moffitt, 1987; Woodward, 1987). 
The underlying concepts of triangulation are fairly simplistic 
and a number of similarities can be drawn with the field of close 
range photogrammetry. These similarities relate to both the 
computational and logistic requirements of the method. 
Until recently digital photogrammetric equipment and 
techniques were not sophisticated enough to match the accuracy 
attainable through the use of first-order theodolite systems. 
Fortunately developments in large area CCD sensors and target 
image location algorithms have pushed the accuracy attainable 
using digital photogrammetry to a level where it can 
comfortably challenge theodolite triangulation systems. (Fraser 
and Shortis 1995). In a modern vision metrology system for 
industrial measurement, object space positional accuracies 
surpassing 1:100,000 of the principal dimension of the object 
are now routinely attainable with large-area CCD cameras and 
photogrammetric data processing (Fraser et al, 1995) High 
resolution still video cameras such as the Kodak DCS460 have 
CCD arrays of up to 2000 by 3000 pixels are readily available, 
thus representing a significant improvement on earlier examples 
of still video cameras. Target image location algorithms such as 
the weighted centroid have theoretical accuracies of 
approximately 1-2% of the image pixel size and have been 
utilised in many videometric applications. 
This paper reports on the suitability of digital photogrammetry 
as an alternative measurement technique for applications that 
have traditionally been completed using theodolite 
triangulation. The discussion is carried out with reference to 
182 
the particular features of both triangulation methods as well as 
factors governing their application. The features and factors 
examined are shown in Figure 1a and Figure 1b respectively 
The paper examines a case study where digital photogrammetry 
was successfully used as an alternative to  theodolite 
triangulation. Digital metrology techniques were utilised to 
determine three dimensional coordinates of key points 
necessary to model the spatial relationship between three 
critical openings of a large furnace hopper assembly (Ganci and 
Shortis, 1995a). Determination of the flange thickness of one of 
these openings was the primary objective of the project. Both 
measurement techniques discussed in this paper were 
considered for the project with the digital photogrammetric 
approach emerging as the favoured choice. The factors 
influencing the metrology method selected are discussed, along 
with the measurement results obtained and other project 
logistics. 
Cost Of Use Potential 
<S FEATURES | > 
Online Target Operational 
Capabilities Requirements Personnel 
Figure la: Features defining the measurement methodology 
  
  
  
  
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B5. Vienna 1996 
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