Buildings Detection and Description System From Multiple Views

Abstract

A method for detection and description of rectilinear buildings from two or more aerial intensity images is described. The multiple images may be taken at different times with differing imaging conditions. Detection and description of buildings under these conditions is a difficult task. It is not possible to compute a dense 3-D map just by intensity correlation. Instead, we need to match features and organize the features into coherent structures. We describe a hierarchical perceptual grouping and matching technique for this. The grouping and matching are performed at several levels, each higher level having more information to make its decisions. The grouping process gives rise to 3-D hypotheses for roofs of buildings which are then further examined for evidence of expected walls and shadows on the ground. The output of the system is a model of 3D building hypotheses, each with an associated confidence measure. Some experimental results are presented.

Block Diagram of the System

Fort Hood Site: Preliminary Example

Fort Hood Examples

Examples

This example shows uncombined buildings. The views used are almost nadir, though they are taken at different times of the day as evidenced by the different shadows. There are a number of bushes, trees, grass patches, vehicles, and small structures in these views.

This example shows one L-shaped building, and two rectangular buildings. One view is a nadir, while the other is an oblique view. There are three buildings in this snippet of the scene, one of which is a gabled-roof building.

This example shows elongated T-shaped buildings. One view is a nadir, while the other is an oblique view. The routine for combination of rectangular 3D building hypotheses was run recursively on the 3D rectagular fragments of the building that were verified, as in the example above. The area surrounding the buildings is fairly busy in terms of density of features detected.

This example shows elongated T-shaped buildings and a building with small extensions. One view is a nadir, while the other is an oblique view. These buildings have significant wall areas visible. The elongated T-shaped buildings are very different in contrast in both views.