Mapping from fused high resolution satellites stereo imageries
Sharawi, Ashraf
With the availability of multisensor, multitemporal, and multiresolution image data from operational Earth observation satellites, the fusion of digital image data, became a valuable tool in remote sensing image evaluation. Fused images provide increased interpretation capabilities and more reliable results, since data from different characteristics, are combined. Therefore, the aim of image fusion is to integrate complementary data, in order to obtain more information, than can be derived from single-sensor data alone. Consequently, the main objective of this paper is to assess the accuracy of maps, produced by image fusion technique from high resolution single optical IKONOS image, and stereo SPOT-P imageries. To achieve such an objective, eighteen sharp and well distributed check points are chosen on both the reference (aerial orthophoto map, covering the El-Moqatum Plateau, Naser City, Cairo, Egypt) and the resulted geo-corrected and geo-coded images (IKONOS + Left and IKONOS + Right fused images) for the same region. Ten points from them ware measured on the flat terrain and the other (8 points) are measured on the top of buildings. Then, their coordinates ware measured and transformed using well defined and good distributed common points over the same area. Finally, discrepancies of coordinates of those points are evaluated. The Root Mean Square (RMS) error of positional discrepancy, in easting and northing directions, is computed. The results showed that, geo-corrected single IKONOS images, as well as the geo-coded fused images (single IKONOS and SPOT-P), corrected using GCPs derived from orthophoto maps of scale 1:10,000, is acceptable by the American National Map Accuracy Standard (NMAS) specifications in production and updating of maps with scale 1:20,000 (practical mapping scale of 25,000) or less, in case of flat terrain, and the geometric accuracy of the top of buildings is worst than that of the points on the flat terrain, which is true due absence of DEM. Regarding the qualitative assessment, there is an increasing description or detectability for the different land use features, in the new fused images compared to the original single images alone, which helps strongly in photo interpretation results.
Event: XXIII International FIG Congress : Shaping the change
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