Photogrammetric Engineering & Remote Sensing · 2010 · 114 citations · 5 references
Natural SciencesEarth SciencesGeoinformaticsGeodesyGeomaticsRemote SensingElevation Data AcquisitionGeometric CorrectionPhotogrammetric Elevation ModelingPhotogrammetric SurveyingPhotogrammetryTerrain MorphometryDem Accuracy AssessmentHorizontal Accuracy AssessmentImage OrientationLaser AltimetryMapping Accuracy EvaluationPositional AccuracyPositional Accuracy EvaluationVertical Accuracy Assessment
This paper examines the positional accuracy of the declassified KH-9 Hexagon imagery and derived DEM. Aimed at geodesy and mapmaking, the KH-9 program (1973 to 1980) resulted in an image archive with worldwide stereo coverage at 6 to 9 m. We used six KH-9 images acquired in 1980 over two testfields in Central Asia. Using reseau marks on the scanned KH- 9 frames, we found and corrected image distortions. In bundle orientation with Ground Control Points (GCPS) from QuickBird images, we achieved horizontal accuracies below 6 m for a flat terrain testfield and approximately 10 m for a mountainous terrain testfield. With three GCPS the image orientation horizontal accuracy degraded by only 20 percent. We generated a DEM from the KH-9 images and estimated its vertical accuracy using IceSAT laser altimetry data and an additional DEM from 1:25 000 topographic maps. The DEM RMSE was 6.18 m over flat terrain and 20.0 m over mountainous terrain.
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