Automatic DEM Generation from Discrete Points in Multiple Images

Abstract

One of the major difficulties in automatic DEM generation is the procurement of approximate values. In this presentation a new development based on the extraction of discrete points by an interest-operator and epipolar line intersection techniques in multiple overlapping images will be shown. The method can be considered an extension of the well-known MATCH-T approach from a stereo technique to a multi-image technique based on image quadruplets in a 60/60 block or even 6 images of a 80/60 block, and it solves the problem of provision of approximate values inherently. In contrast to most stereo-based techniques, the approach is not based on image pyramids, but on the consequent exploitation of the geometric strength of multiple images, implemented via the intersection of epipolar lines. Although not outlined for a complete DEM generation yet, the method may be very valuable for a hypothesis-free generation of good approximate values for other (e.g. area-based) DEM generation techniques or for the refinement of DEMs degraded by smoothing effects.