Change detection in urban areas using Very High spatial Resolution satellite images - Case study in Brussels: Locating main changes in order to update the Urban Information System

In this paper we examine the possibilities of using VHR images for locating major changes (of buildings, roads and vegetation) in order to focus ground topographical measurements and to keep a topographic 1:1000 database (UrBIS) of urban areas up-to-date in between two aerial photographic flights. The techniques implemented were multi-temporal classification and post-classification change detection. The first method consisted of a multi-temporal coloured composition classification. Main changes were well detected, though a number of "false changes" were detected and remain significant. Solutions to reduce the number of false alarms will be investigated through the application of post-classification rules. The second method tested could not be completed thus far, however, results of the hierarchical classification of a VHR image are shown.