A system for obtaining three-dimensional information about a surface, the system comprising: a sensing device having: a pattern projector for providing a projected pattern on the surface; and a camera for acquiring a 2D image of the surface from a viewpoint, wherein at least one target of a set of reference targets and at least a portion of the projected pattern is apparent on the 2D image; a storage for calibration data; an image processor for extracting 2D image coordinates of surface points of the projected pattern and target contours from the 2D image; a 3D surface point calculator for calculating 3D coordinates of the surface points from the 2D image coordinates of the surface points; a 3D target calculator for calculating a 3D position and/or an actual orientation for the reference target.