True Ortho-photo Generation from High Resolution Satellite Imagery

Abstract

Ortho-photos contain highly valuable data with high potential. They are useful in various applications, such as the creation of image maps and texture information in Geographic Information System (GIS). The Z-buffer method has been one of the most popular methods for the true ortho-photo generation. However, it has strict requirements regarding the Digital Surface Model (DSM) cell size. Furthermore, Z-buffer Method have false visibility problmes in narrow vertical structrues. The Z-buffer Method can be modified to avoid this problem using pseudo points along vertical surfaces. However, this method still has problems with certain DSM resolutions. This study implements two technical approaches for true ortho-photo generation u(l) the horizontal position of a point along the search path reaches the nadir point in the object space sing high resolution satellite imagery. The first approach deals with the scan line search method, which is required since each scan line has its own perspective center. The other approach is concerned with occlusion detection, which is required for the creation of true ortho-photos. Final experimental results with real data have demonstrated the feasibility of this proposed true ortho-photo generation methodology.