HIGH-PRECISION OBJECT MONITORING WITH IMAGE ASSISTED THEODOLITES - STATE OF THE ART 1

In the past, high-precision online 3-D measuring required artificial targets defining the points on the objects to be monitored. For many tasks like monitoring of displacements of buildings, artificial targets are not desired. Todays image assisted theodolite systems can perform their measurements even without targeting. Such systems use the texture on the surface of the object to find "interesting points" which can replace the artificial targets. However, well-trained "measurement experts" are required to operate such a measurement system. In order to make such systems easy to use even for non-experts, it can be extended by an appropriate decision system which supports the operator. We report on the state of the art of such image assisted theodolite measurement systems and on the potential of future developments. Mainly, research work carried out at the Vienna University of Technology and Leica Geosystems (Heerbrugg) will be described here.