Abstract: Measuring 3D coordinates based on point correspondences from a set of images is useful in many fields, but it only provides a coarse depth map of the object. To obtain a dense depth map, it’s a feasible way to combine shape from shading and point correspondences. Correspondences technique is first used to get a coarse depth map; then a constrained triangulation method is used to insert interpolation points in the image plane; at last , a triangle element formulation is used to integrate information from SFS (shape from shading) with that from point correspondences. A multi-grid finite element method is also put forward to solve the formulation. Example shows that the method is satisfied.

Key words: Finite element method, Photogrammetry, Point correspondences, SFS, Triangulation