JPS6444805A - Calibrating method of position and posture of pattern projector - Google Patents

Abstract

PURPOSE:To simplify and expedite the calibration of posture and to make it highly precise and highly stable, by a method wherein the three-dimensional position of each characteristic point of a projected pattern on a pickup plate is measured by two cameras whose image pickup positions are calibrated beforehand, and each characteristic point is made to correspond to each characteristic point of the original picture of the pattern. CONSTITUTION:A pattern original plate 4 is projected on the surface of an object W of measurement by a pattern projector 2. Three-dimensional positions of a group of projection points on the object W of a group of six or more characteristic points on said original plate 4 are measured at multiple points simultaneously or in a time- series manner by using one pickup camera 1 or more whose pickup position and posture are already calibrated. Using the three-dimensional positions of the group of the characteristic points thus obtained and the coordinate values of the group of the characteristic points of a pattern on the original plate 4 corresponding thereto, the correlative relationship between a spatial coordinate system and a coordinate system of projection of the pattern is calculated by a matrix computation. The projecting position and posture of the projector 2 are calibrated simply and highly precisely from the correlative relationship thus obtained.