POLYGON-BASED TRUE ORTHOPHOTO GENERATION

Obscured areas are serious defects in large-scale and urban orthophotos. In recent years several rectification schemes minimizing these defects were proposed. These methods use raster-based algorithms for the detection of obscured areas and reconstruction of true orthophoto images. The common drawbacks of image-based approaches are that they require a lot of additional memory for intermediate structures and are slow and resolution dependent. In our paper we propose to use a polygon-based algorithm for the detection of obscured areas. Such a polygon-based approach is fast, accurate, and resolution independent. Spatial overlay processing provides the selection of the best orthophoto image for the recovery of detected obscured areas. The proposed method allows easy integration of true ortho image reconstruction techniques with existing commercial image processing software and spatial analysis tools