Satellite Digital Elevation Model on the heterogeneous OPENVISION parallel computer

Abstract

The goal of the Digital Elevation Model is to generate an accurate three-dimensional scene using a stereo vision technique. In the stereo matching process two techniques are utilized, an area-based and feature-based to generate a disparity map. In our application we use an area-based approach coupled with the prediction validation techniques. The computation of the Digital Elevation Model (DEM) is based on correlation, also called matching, to determine the pixel correspondence in a pair of stereo spatial images. It is a fundamental step in digital mapping. The French "Institut Geographique National" (IGN) has developed a system to provide DEM. The kernel of this system is based on an incremental correlation method, which is the bottleneck in the map production because of its expenditure of computing time. In the same way the CEA-LETI has developed in collaboration with the IRIT laboratory (Toulouse University), a SIMD calculator SYMPATI2 dedicated to image processing, and integrated in the OPENVISION real-time system. The IGN DEM of SPOT images (6000/spl times/6000) takes 20 hours using a Sparc 10 workstation. In order to reduce this computation time we studied the parallelization and the implementation the IGN algorithm on OPENVISION.