Orthorectifying stitched oblique imagery to a nadir view, and applications thereof

摘要

Embodiments of this invention relates to orthorectifying oblique imagery to a nadir view. In an embodiment, a method orthorectifies oblique photographic imagery. An oblique photographic image is projected onto a three-dimensional model of terrain. Points are sampled from the projected photographic image at the intersection of the three-dimensional model of terrain and parallel rays extended from a virtual viewport having a nadir perspective. The sampled points are assembled into an orthorectified image. Finally, the orthorectifϊed image or the sampled points are adjusted approximately according to a difference in tilt angle between a camera that captured the oblique photographic image and the viewport having the nadir perspective to generate a foreshortened orthorectifϊed image. Each location in the foreshortened orthorectifϊed image corresponds linearly to a corresponding location in a two-dimensional map.