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2.1 SPACE - A Theodolite measuring system 
Precise theodolites with photoelectric graduated circle 
reading form the basis of this system. A beam-splitter 
makes it possible to project the object onto a CCD- 
sensor and to make a regular observation using an 
ocular. Defined points can be targeted under computer 
control and, providing the system consists of at least two 
theodolites, their spacial coordinates calculated. The 
targeting of the theodolite is performed either manually 
or, given initial values, by computer. The first step in 
precisely measuring a direction is to align the optical 
axis of the theodolite so accurately that the point is 
projected onto the CCD-sensor in the telescope. The 
second step is to measure the centre of the point in the 
digitized image using, in this case, an algorithm based 
on the moment preservation method [Zhou 1986]. The 
expected accuracy lies in the order of 0.2 to 0.4 mgon 
for well defined points. 
A system consisting of two theodolites was provided by 
the Physikalisch-Technische-Bundesanstalt, — Braun- 
schweig for this test. 
  
Fig. 1 E2-SE, motorized, electronic theodolite with 
integrated CCD-sensor 
2.2 Large Format Camera (LFC) 
This system, which was designed for highly accurate 
industrial photogrammetry, is used primarily for object 
measurements in which the object can only be recorded 
for a very short time. Synchronization of several 
cameras allows the recording of dynamic processes in 
sections. The LFC combines analogue recording 
techniques consequentially with the réseau technique. 
Correction of film unflatness, e.g. using a vacuum plate, 
is not necessary here. Film unevenness on recording 
and film deformations are largely compensated for on 
measurement with the Réseau- Scanner. Typical 
measurement accuracy is between 1 - 2 um. 
For safe, reliable identification, the measured points 
should preferably be made of retro-reflecting material. 
This method of point targeting has already been 
successful in many projects [Brown 1984, Dold and 
Riechmann 1991]. The necessary réseau for optical- 
numeric transformation is projected onto the film by a 
pre-exposure unit. Automated image coordinate 
determination then takes place by means of the 
Réseau-Scanner RS1 [Luhmann 1988]. 
  
Fig. 2 Large Format Camera (LFC) 
2.3 Rolleiflex 6008 metric 
Building on the positive experiences made with the 
partial-metric camera Rolleiflex 6006, the successor is 
equipped with a fine-mesh réseau (1.75 x 2.375 mm?) 
and a special pre-exposure unit. Film unflatness and 
deformities can be corrected by this fine-mesh réseau 
so well that measurement accuracy of 1pm and better is 
attainable [Suilmann 1992]. A great advantage of this 
camera is the multitude of electronic aids found in a 
professional camera, which greatly ease operation. 
Object lenses with focal lengths ranging from 40 mm to 
120 mm and more are available to solve various 
problems in industrial applications. 
2.4 Réseau Scanning Camera (RSC) 
The RSC was designed for high-resolution on-line object 
recording using a standard CCD-sensor. The CCD is 
placed in the image plane of a camera - in this case a 
mid-size camera. A shifting device is used to move the 
sensor both within the image plane and perpendicular to