Automated aerotriangulation using multiple image multipoint matching

This paper deals with automating the aerotriangulation procedure using digital image processing methods and images available exclusively in digital format. A conceptual system has been developed and implemented which allows for the automatic determination of exterior orientation parameters and positions of selected points in object space using a minimal number of assumptions. In direct analogy to the preparation phase of the conventional approach, a photomosaic is automatically generated to describe the interrelationship of all photos within the available block. This photomosaic is subsequently used for the automatic extraction of approximate conjugate image coordinates. A multiple image multipoint matching strategy has been developed to identify and precisely match conjugate points in the triple, quadruple, or multiple overlapping areas of the block. By taking into account the geometric relationship between conjugate points as expressed by their corresponding image-forming rays, and using image coordinates rather than the widely used local template coordinates, matching and block adjustment can be combined in a unique way. Thus, the mensuration and adjustment phases of classical aerotriangulation are substituted by a single digital process which allows automation of the complete procedure.