Digital Surface Modelling from Spot 5 Hrs Imagery Using the Affine Projective Model

This paper presents the results of work carried out under the auspices of the joint ISPRS CNES Scientific Assessment Program of DEM generation from SPOT 5 high resolution stereoscopic (HRS) image data. A stereo pair of HRS images of Melbourne, Australia, with a ground sample distance of 5m in the along track direction, and 10m in the across track direction, was used to create digital surface models of varying grid spacings of the urban area surrounding the city of Melbourne. Conjugate points from the SPOT stereopair were located using intensity based image matching, and triangulated using the affine projective model. The resultant digital surface models were compared to precisely located ground control points and a reference digital terrain model. The results showed that high quality digital surface models can be produced from HRS image data using the algorithms described. The comparison between the surface model and ground control points revealed an RMS height error of 3-5m or 0.6-1 pixel.