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T. Vicovac, A. Reiterer, D. Rieke-Zapp:
"6th TOPO‐EUROPE Workshop";
Poster: 6th TOPO‐EUROPE Workshop, Honefoss, Norwegen; 2010-11-04 - 2010-11-07.

Risk assessment of rockfalls and landslides requires an accurate evaluation of the geology, hydrogeology, morphology and interrelated factors such as environmental conditions and human activities. It is of particular importance for engineers and geologists to assess slope stability and dynamics in order to take appropriate, effective and timely measures against such events.
The main goal of our work is the development of a deformation measurement and interpretation system for geo-risk monitoring. The implementation of a decision support system enables an automatic process of interpretation and determining of the risk potential.
Making conclusions about incidents is a not-trivial problem; by using artificial intelligence techniques, via the integration of a knowledge-based system, new directions are opened up. This new system is a complex decision support system, working with several different data sets in real-time. Deformation measurement data will be delivered by a novel type of measurement system, which consists of two image-based sensors. Inside the captured images so-called interest points are detected. The calculation of the 3D coordinates is done by classical geodetic forward intersection. By means of such a high precision measurement system, 3D object points can be detected with an accuracy of about 2-3 mm (object distances up to 1000 m). Subsequently a geodetic deformation analysis can be performed that yields as a result deformation movement vectors, which constitute the input for later interpretation.
Based on the measured deformation vectors, a measurement preprocessing is performed (mainly clustering to detect areas of similar movement). On the basis of this information and additional data about velocity and orientation, some conclusions about the kind of occurring movement can be drawn. Additionally, data of different, heterogeneous sources, such as geodetic deformation measurements, geotechnical measurements, geological maps, geomorphological maps, in-situ investigations, and numerical modeling methods have to be included in such a system.
The concept of data interpretation is based on the "calculation" of risk factors for critical cause variables and on the elaboration of an interpretation for the deformation. Examples for cause variables can be precipitation, permafrost, critical slope angle, etc.
The challenging problem in developing such an alerting system is (1) to identify relevant factors and (2) subsequently to capture the interlinkage of these influence factors.
In our system, the process of risk assessment is divided into two steps: (1) the determination of the "Initial Risk Factor" and (2) the determination of the "Dynamic Risk Factor". The first step estimates the plausibility of an occurring moving event. Furthermore the zero state of interpretation and the observation is defined.
The second step is focused on the processing of the temporal development of the risk factor. Therefore additional data have to be included into the decision process, e.g., measured data captured by the image-based monitoring system.
In order to further improve the quality of risk assessments of the system and to test its usability, we initiated an even broader evaluation where we asked experts for their opinion on our test cases. These experts should bring in a fresh sight on the problem and the system because they have no information about the system and no training on it. The results obtained from first new probands are in accordance with the system and with the former evaluators. This also shows that the system interface is intuitive enough such that an untrained expert can easily use it without major difficulties.

monitoring, change detection, image-based measurement

http://publik.tuwien.ac.at/files/PubDat_194324.pdf