A Novel Method for Detecting and Identifying Road Junctions from High Resolution SAR Images

Abstract

Road junctions are important parts of the road network, and have a major role in GIS database updating, image matching, object detecting, and so on. In high resolution SAR images, there exist various kinds of interference on the road, and the contrast is not obvious between roads and surroundings. It is difficult to extract road junctions by traditional methods. A new method is proposed for directly detecting and identifying road junctions in this paper. Firstly, based on the junctions gray feature, global searching is done for the center positions of the road junctions’ candidate regions, by using morphological transformation methods. Secondly, the center positions are set as the local windows centers, road targets are segmented by using the multi-threshold Otsu method in the local windows. Thirdly, according to the geometric characteristics of junctions, we obtain the angle-mean figure in the rectangular template rotation process, and then get the number of the roads connected to a junction. Finally, the style of the junction is recognized. In 1 m high-resolution airborne SAR image experiment, the results indicate that this method is effective to detect and identify the junctions with various interferences.