Object surface characterization using optical triangulaton and a single camera

Abstract

Electromagnetic radiation is directed from an optical grating in a regular array of beams in rows and columns toward a target object surface; and the reflected beams are focused through a lens to form beam images on an image plane of a single camera. Each of the beam images has a position on the image plane that moves substantially linearly with variation of a target distance between the optical grating and a point on the object surface from which that beam image is reflected; and the direction of the substantially linear movement of each beam image forms a predetermined angle with the column of the array of beam images on the image plane to which that beam belongs at a common target distance. Positional data for each of the beam images on the image plane is derived and provided to a processor which uses stored reference data defining predetermined beam paths in the image plane for the beam images to locate and determine the associated one of the predetermined beam paths for each of the beam images on the image plane, determine the location of each of the beam images along its associated predetermined beam path, determine the target distance for that beam and store an array of the determined target distances for each of the located beam images to characterize the object surface. The predetermined angle may provide for each beam having a separate predetermined beam path. For greater resolution, some of the beam paths may have two associated beams, and processing is provided to distinguish the beams on a single beam path uniquely.