Patent ID: 7286246
Filing Date: 2007-10-23
Classification: G01B

Abstract:
1. A non-contact three-dimensional surface measurement method comprising the steps of: observing a grating pattern projected onto an object being measured, while a phase of the pattern is being shifted, in a different direction from a projection direction; analyzing contrast of a grating image deformed in accordance with a shape of the object and thereby obtaining the shape thereof; shifting focuses of the projection and imaging sides back and forth continuously, by altering a position of a grating filter and an imagine device with respect to a projection lens and an imaging lens, respectively, to enlarge a measurement range in a direction of depth; successively entering image data of the object while the focus and the phase are being shifted at a constant speed; and preparing a three-dimensional map by processing the entered data in a computer, by determining an order of a fringe from a focal center and unwrapping the phase to calculate an absolute value of the phase, and calculating a three-dimensional position of a point of intersection of a grating plane of the fringe order and an epipolar line of an imaging point.