Detection and classification of circular structures on SPOT images

An unsupervised method for detecting structural features on satellite images that consists of three major steps is proposed. The extraction of contours, which depends on the texture encountered is achieved by an iterative filtering followed by several thresholds that generate binary images. The detection of the structures from the contours involves four substeps: individualization of the curves; decomposition of the curves into subcircular elements; application of a version of the Hough transform to each subcircular element; and computation of precise results. The parameters that discriminate the structures are computed. These data allow the selection of different families of structures that are being looked at. The method has been applied to the region of Azru