期刊名称：ISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Information Sciences
印刷版ISSN：2194-9042
电子版ISSN：2194-9050
出版年度：2004
卷号：XXXV Part B3
页码：693-697
出版社：Copernicus Publications
摘要：It is the traditional procedure to generate orthophotos from aerial photographs by differential rectification. The effects of relief displacement are corrected by considering a Digital Terrain Model (DTM). Due to the fact that DTM's do not describe the surface of buildings, bridges, trees etc. such objects remain in perspective views in the resulting orthophotos. If a Digital Surface Model (DSM) describes the mentioned objects, the caused displacements can also be corrected, and the results are called "True Orthoimages". However, recent developments of optoelectronic cameras like HRSC or ADX 40 allow for a totally new approach for orthoimage generation. The nadir-looking channels of these cameras provide image data in parallel projection along the flight line, and in central perspectives across. If a scene is imaged twice in flight lines perpendicular to each other, the first image strip provides correct ground coordinates of any object in one direction, the second image strip in the other direction. The new approach takes advantage of these particular geometric properties. It is based on the definition of corresponding points in the image data sets by means of matching techniques or corresponding areas by means of segmentation procedures. Each conjugate point directly provides the correct ground coordinates and can be assigned as a pixel to the orthoimage. Thus, a true orthoimage is generated without any knowledge of the object heights or further calculations. The paper provides a detailed description of the approach, and its advantages and limitations are discussed
