Stereocorrelation on the parallel OPENVISION system

The aim of this work is to reduce the computation time needed to produce the Digital Elevation Models (DEM) by using a parallel machine. It is made in collaboration between the French “Institut Geographique National” (IGN) and LETI-DEIN, a department of the French Atomic Energy Commission (CEA). The IGN has developed a system which provides accurate DEM, that is used to produce the commercialized topographic map. The kernel of this system is the correlator. The correlator is a part of software which automatically matches pairs of homologous points (i.e. a pair of points representing the same ground detail), and supplies disparities. Nevertheless the correlator is expensive in computing time. CEA-LETI. is involved in parallel architecture and image processing and has developed a SIMD (Single Instruction Multiple Data) parallel architecture called SYMPATI 2. This structure constitute the kernel of the parallel OPENVISION system that is commercialized by Centralp Automatisme. In order to reduce the computation time and to produce the DEM with the same accuracy than the scalar approach, this two partners tried to parallize the IGN´s correlator on the OPENVISION system