Patent ID: 7595894
Filing Date: 2009-09-29
Classification: G01B

Abstract:
1. A profilometry apparatus, comprising: a fringe projection device configured to project a fringe pattern on an object; an optical unit configured to capture a single set of pixel data corresponding to a single captured image of a distorted fringe pattern modulated by the object; and a programmable signal processing unit configured to process directly the single set of captured pixel data from the optical unit to filter noise from the image and extract a pixel phase map of the distorted fringe pattern there from to obtain real-time estimation of parameters associated with manufacture or repair of the object; wherein the single captured image is represented as I k (i,j)=I o (i,j)[1+γ(i,j)cos(φ(i,j)+δ k )], k=1,2,3 . . . K, wherein k is the index number of the sub images used in the phase measurement, I is the intensity at pixel (i,j), I o is the background illumination, γ is the fringe modulation representing image contrast, δ k is the initial phase for each individual image k, and K is the total number of index sub images; and further wherein filtering noise from the image comprises obtaining a two dimensional Fourier transform for I the pixel phase map is extracted directly from a plurality of pixel phase values determined from a set of complex numbers generated for the band-pass filtered two dimensional Fourier transform that is inverse transformed to generate the set of complex numbers.