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:2007
卷号:XXXVI-1/W51
出版社:Copernicus Publications
摘要:Due to legal restrictions, the German hard coal mining company Deutsche Steinkohle AG (DSK) is obliged to conduct a monitoring on surface changes (subsidence) caused by mining activity (e.g. topographic surface, groundwater, water, flora and fauna, soil). To fulfill legal demands and to do this effectively, process chains by use of Photogrammetry, Remote Sensing and Geo Information Systems (GIS) have been established. Photogrammetric methods are used to generate high resolution Digital Elevation Models (DEM) from which in combination with subsidence data geometric changes at the topographic surface are deduced. For mine site areas from about 100 km2 to 200 km2 DEMs have to be handled on digital photogrammetric stereo workstations with a height standard deviation of ±10cm. This accuracy up to now could be obtained with analogue wide angle cameras at an image scale of 1:4000 and 80% end lap together with a high number of ground control points (GCP). More and more digital aerial frame cameras like Intergraph DMC and Vexcel UltraCamD are available for mapping application. DSK decided to order photo flights with the Vexcel UltraCamD because only this camera is able to take images at 80% end lap with a ground sampling distance (GSD) of 10cm. A vertical accuracy of about ± 8 to 9cm should be reached. Since 2004 three digital photo flights have been made for DSK with the same camera, no. 8. In December 2004 for the stereo plotting of a site plan for a coking plant, in August 2005 a test flight covering 20 km2 has been made to evaluate the potential of color-infrared images for environmental monitoring purposes and in March 2006 an aerial photo flight for DEM generation of a mine site followed. The stereo plotting showed differences in height of about 25cm for neighbored 60% stereo models based on systematic effects in the digital aerial images. DSK noticed that usual commercial digital photogrammetric workstations were not able to handle systematic image errors determined by bundle block adjustment. The model deformations were acceptable for the horizontal coordinate components, but in the height, deformations exceeded the accuracy limit. The program DEMCOR has been generated at the Institute of Photogrammetry and Geoinformation, Leibniz University Hannover, for a posteriori correction of DEM and the program IMGEO for the resampling of the images for accurate stereo-measurements. So the full accuracy potential can be reached. This paper presents the comparison of UltraCamD and analogue RMK TOP 15 DEM as well as the systematic image errors of a DMC (photo flight Frederiksstad). The photo flights have not been made with the now available latest versions of DMC and UltraCamD processing software. In the meantime Intergraph and Vexcel modified the cameras and the data handling. The described geometric problems still exist for analogue cameras, but they are usually ignored
关键词:digital aerial cameras; geometry; model deformation; stereo plotting