Detection of Bridges using Different Types of High Resolution Satellite Images

Automatic detection of geographical objects such as roads, buildings and bridges from remote sensing imagery is a very meaningful but difficult work. Bridges over water is a typical geographical object and its automatic detection is of great significance for many applications. Finding Region Of Interest (ROI) having water areas alone is the most crucial task in bridge detection. This can be done with image processing / soft computing methods using images in spatial domain or with Normalized Differential Water Index (NDWI) using images in spectral domain. We have developed an efficient algorithm for bridge detection where the ROI segmentation is done using both methods. Exact locations of bridges are obtained by knowledge models and spatial resolution of the image. These knowledge models are applied in the algorithm in such a way that the thresholds are automatically fixed depending on the quality of the image. Using the algorithm any type of bridges are extracted irrespective of their inclination and shape.