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LOW COST SURVEYING SYSTEMS IN ARCHITECTURAL PHOTOGRAMMETRY 
Manfred Fellbaum 
Institut für Photogrammetrie und Bildverarbeitung 
Technische Universitat Braunschweig 
FRG 
Commission V 
0 Abstract 
In recent times quite a few new photogrammetric sytems, especially in architectural 
photogrammetry, have been introduced to the market. The main difference to the older 
existing surveying systems is, that the new ones are not very expensive. This paper tries 
to give a survey concerning these low cost systems. It wants to outline the principles of 
photogrammetric evaluation, and give some examples. 
1 Introduction 
This paper gives an overview on existing low 
cost photogrammetric systems. The reason for 
the coming up of these systems, is the need of 
a general accessibility of  photogrammetry, 
especially in architecture. For many users 
conventional analytical plotters are too 
expensive. Often, the performance of those 
systems is not necessary. There are low cost 
solutions required, which are cheap, flexibel, 
compatible, versatile, and easy to use. 
Therefore all of the systems, which will be 
presented in this paper, are menu driven and 
use hardware which is compatible to IBM 
personal computer and standard plotters. This 
overview cannot be complete. The author has 
tried to describe different principles by means 
of a number of representive systems. 
2 Monoscopic Image Measurement 
Monoscopic measurement of image coordinates 
requires rather simple instrumental devices 
(Fig. 2.1), and therefore offers an important 
presupposition for low cost photogrammetric 
systems. On the one hand, these systems don’t 
offer the opportunities of conventional stereo 
photogrammetry, on the other hand monoscopic 
image measurement fits very much to multi- 
image-triangulation, carried out by 
simultaneous bundle adjustment. Within the 
multi image bundle adjustment a self 
calibration of the used cameras can be done. 
This increases the reachable accuracy of these 
systems and allows the use of non-metric and 
partial metric cameras [WESTER-EBBI NGHAUS 
1985]. Control information is not restricted to 
three dimensionally predetermined object 
points. It is possible to introduce geodetic 
measurements like distances, directions etc.. 
Low cost devices for monoscopic image 
measurement are high resolution monocomparators 
with image carriers for negative film (Fig. 
2.2), ‘digitizing tablets (Fig. 2.3), and 
computer monitors with digital image processing 
hardware (Fig.2.4). 
3 Stereoscopic Image Measurement 
Due to the stereoscopic viewing of the images, 
this kind of measurement requires more complex 
measuring instruments than the above mentioned 
monoscopic principle. Besides the advantages of 
stereo viewing however most of these systems 
don't offer the option of a multi image 
orientation. This makes simultanous camera 
calibration more difficult. If no calibration 
is possible at all, only metric cameras can be 
used in connection with such a system. The 
systems can be divided into stereocomparators 
(STC) and analytical plotters. For the latter a 
subdivision into Image-Space-Plotters (ISP) and 
Object-Space-Plotters (OSP) is possible. 
Measurements with either instrument can be done 
on an image carrier with negative film, a 
digitizing tablet, and a monitor with digital 
image processing hardware (Fig. 3.1). 
  
  
  
  
  
  
  
monoscopic 
measurement 
devices 
digitizing computer image 
tablet monitor carrier 
  
  
  
  
  
  
  
  
Fig. 2.1 Devices for monoscopic image 
measurement 
image carrier 
with measuring device 
image / 
| ANC microscope 
| with measuring mark 
| — [operator | 
image 
carrier .—— x y [25r ay 
control 
  
  
  
  
  
  
  
  
  
  
  
  
  
Fig. 2.2 Measurement principle of à 
monocomparator