Accuracy evaluation of DEM generated using Radarsat stereo images

Abstract

In this paper we present some results on the accuracy of planimetric, and altimetric data generated from a stereo-pair of Radarsat images acquired over Hong Kong which has a generally rugged topography. In our analysis, an assessment of the orbit quality is first made with suitable ground control points (GCPs) obtained from high resolution (1:20,000) contour maps of the region. Here we compare ground coordinates of the GCPs generated within the standard Radargrammetric analysis with those available from the contour maps. Essentially, the residues provide a measure of the inaccuracies in the satellite's state vectors. We then apply an automatic matching algorithm to register the images. The quality of the registration is assessed by comparing the disparities of tie-points obtained through the automatic procedure with those obtained manually. We also provide estimates of the root mean square errors in both the planimetric and altimetric data obtained through the automatic procedure.