ACCURACY IMPROVEMENT OF DEM FOR GENERATING ORTHOPHOTO BY REVERSE PROJECTION METHOD

Abstract. The generation of orthophotos using digital aerial photography is performed for the maintenance of spatial information data for wide areas at the mid-scale.For orthophoto generation, a digital elevation model (DEM) based on stereo matching methods is widely used, the accuracy of which should be effectively improved by removing mismatched points created during the stereo matching process for efficient orthophoto generation.With this motive in mind, a new method called the “Reverse-Projection Method” is proposed to remove mismatched points from DEM generation. The most remarkable points of this method are its ability to detect mismatched points and improve the accuracy of a DEM using only stereo models on the previous and following strips and restricting the higherresolution stage in the coarse-to-fine approach using the Digital Terrain Model as a reference. The effectiveness of the method is discussed in this paper.