<title>Road detection from aerial images: a cooperation between local and global methods</title>

We present in this paper a road detection method based on the cooperation between a road following algorithm and a global method which consists of a whole image segmentation followed by a characterization of regions (using shape and texture criteria). One will find there an overview of the approach, a description of the used techniques and then a presentation of the mean we use to make both methods cooperate. Both of our methods are based on quite the same road model (roads are elongated objects with parallel edges and an homogeneous texture) and both try to extract the same kind of roads: the interest of the approach is more to improve the detection reliability for a great part of the network than to look for an exhaustive extraction.