Patent ID: 7912673

Claim:
A system for obtaining three-dimensional surface points of an object in an object coordinate system, comprising: a set of target positioning features on said object, each of said target positioning features being provided at a fixed position on said object, said object coordinate system being defined using said target positioning features; a sensing device having a pattern projector for providing a projected pattern on a surface of said object, at least a pair of cameras each for acquiring a 2D image of said object, said projected pattern and at least a portion of said set of target positioning features being apparent on said images, each of said 2D images being acquired from a view point referenced in a sensing device coordinate system; an image processor for extracting, from said 2D images, at least one set of 2D surface points from a reflection of said projected pattern on said surface, and at least two sets of 2D positioning features from a reflection of said target positioning features on said surface; a 3D surface point calculator for calculating a set of 3D surface points in said sensing device coordinate system using said set of 2D surface points; a 3D positioning feature calculator for calculating a set of calculated 3D positioning features in said sensing device coordinate system using said sets of 2D positioning features; a positioning features matcher for computing transformation parameters to characterize a current spatial relationship between said sensing device coordinate system and said object coordinate system, by matching corresponding features between said set of calculated 3D positioning features in said sensing device coordinate system and a set of reference 3D positioning features in said object coordinate system, said reference 3D positioning features being cumulated from previous observations; a 3D positioning feature transformer for transforming said set of calculated 3D positioning features into a set of transformed 3D positioning features in said object coordinate system using said transformation parameters; a 3D surface point transformer for transforming said set of 3D surface points into a set of transformed 3D surface points in said object coordinate system using said transformation parameters; and a 3D reference positioning feature model builder for cumulating said set of transformed 3D positioning features to provide and augment said set of reference 3D positioning features.