An energy minimization approach to building detection in aerial images

An energy function based approach is presented to detect rectangular shapes in images. The proposed edge-based approach involves extracting straight lines from an edge map of the image. Then a Markov Random Field (MRF) is built on these lines. The energy function associated with the MRF can be construed as a measure of the conditional probability of observing the lines given the rectangular shapes (the positions and number of which are unknown) in the image and the minimization results in a maximum likelihood estimate. This approach, supplemented with some qualitative information about shadows and gradients, is used to detect rectangular buildings in real aerial images. Due to poor quality of the real images, only partial shapes are extracted in some cases. A modified deformable contour (snakes) based approach is then presented for completion of the partial shapes