EuroSDR Projects - Host Ireland

2 Project highlights
The project Change Detection has been carried out by ARC systems research in cooperation with the Austrian
Federal Mapping Agency and a consortium of international partners. This consortium is composed of the following
organisations and their representatives:
- BEV, Austria, Michael Franzen
- BKG, Germany, Andreas Busch
- GCM, Turkey, Oktay Aksu
- IGN, Belgium, Ingrid Vanden Berghe
- KMS, Denmark, Brian Pilemann Olsen
- NLS, Finland, Tapio Tuomisto
- SwissTopo, Switzerland, Andre Streilein.
The first meeting of the consortium took place during the EuroSDR meeting in Madrid in October, 2004. There the
suggested methodology for change detection was discussed (see annex 1 for project presentation) and the partners
agreed to provide data sets. The agreement was presented at the EuroSDR meeting and approved by the science
committee.
The data was provided in the end of 2004 and beginning of 2005. The quality of the image data ranges from black
and white images with rather low radiometric quality to true-colour and colour-infrared images. The scale of the
vector data ranges from 1:1,000 to 1:25,000 with varying levels of generalisation. As the classification procedure
requires true-colour or colour-infrared information and minimum information provided with the vector data, the
case studies had to be limited to the Austrian, German, Danish and Swiss test sites.
First results were presented at the ISPRS workshop on "High resolution earth imaging for geospatial information"
in Hannover, Germany in May, 2005.
In June 2005 a workshop was held at the BEV with participants from nine different countries (see annex 2 for
minutes). First results were presented and discussed with the different project partners. Different adjustments were
suggested and subsequently incorporated in the procedure. The new results were then conveyed to the partners for
evaluation and feedback.
In July 2005 a paper was presented at IGARSS05 conference in Seoul. The paper can be found in annex 3.
The final meeting of the project consortium took place at the EuroSDR meeting in Nicosia in October 2005 (see
annex 4 for presentation and annex 5 for minutes). Final feedback was given by the project partners on the change
detection results and some of their experiments were presented. In general it was felt that the change map is one
possible source for identifying changes but all other available sources must be included as well. Updating data
bases can cost up to 40 % of the cost of data base generation and thus more efficient update procedures are desirable.
This coincides with the need to shorten the update cycles (e.g. from ten to three years). There are different
priorities for different object groups and the update should be adjusted accordingly. The presentation of the change
information must be simple (e.g. traffic light system). If it is too complex the operator would require too much time.
3 Methodology
Automated or semi-automated analysis of high resolution images has been hampered by the high complexity of
such images. Traditional pixel-based classifiers such as Maximum Likelihood very often lead to an undesired
speckle effect (Willhauck, 2000) as they only look at one pixel at a time without considering its spatial context.
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