Structured light 3-D measurement module and system for illuminating a subject-under-test in relative linear motion with a fixed-pattern optic

摘要

A surface measurement module for 3-D triangulation-based image acquisition of a subject-under-inspection and under observation by at least one camera. The module having: (a) casing housing an optical system comprising a plurality of lens elements positioned between a fixed-pattern optic and a light source; (b) an output of said fixed-pattern optic comprising a multi-frequency pattern comprising a plurality of pixels representing at least a first and second superimposed sinusoid projected simultaneously, each of the sinusoids represented by the pixels having a unique temporal frequency and each of the pixels projected to satisfy;Inp=Ap+∑k=1K⁢Bkp⁢cos⁡(2⁢⁢π⁢⁢fk⁢yp+2⁢⁢π⁢⁢knN)Eq.⁢(1.1)
(c) the subject-under-inspection and fixed-pattern optic in relative linear motion during projection onto the subject-under-inspection of the output of the fixed-pattern optic; and (d) plurality of images captured of this output during projection onto the subject-under-inspection are used for the image acquisition.

主权项

1. A surface measurement module for 3-D triangulation-based image acquisition of a subject-under-inspection and under observation by at least one camera, the module comprising:
(a) a casing housing an optical system comprising a plurality of lens elements positioned between a fixed-pattern optic and a light source; (b) an output of said fixed-pattern optic comprising a multi-frequency pattern comprising a plurality of pixels representing at least a first and second superimposed sinusoid projected simultaneously, each of the sinusoids represented by the pixels having a unique temporal frequency and each of the pixels projected to satisfyInp=Ap+∑k=1K⁢Bkp⁢cos⁡(2⁢⁢π⁢⁢fk⁢yp+2⁢⁢π⁢⁢knN)Eq.⁢(1.1)  where Inp is an intensity of a pixel for an nth projected image in a particular moment in time; K is an integer representing a number of component sinusoids, each component sinusoid having a distinct temporal frequency, where K is less than or equal to (N+1)/2, said output comprising at least N projected patterns; a parameter Bkp represents constants that determine an amplitude or signal strength of the component sinusoids; Ap is a scalar; fk is a spatial frequency of a kth sinusoid corresponding to temporal frequency k; and yp represents a spatial coordinate in an image projected as a result of said output; (c) said fixed-pattern optic comprises said multi-frequency pattern fixed into a glass substrate, such that said output thereof results during said projection onto the subject-under-inspection; (d) the subject-under-inspection and said fixed-pattern optic in motion in relative linear motion during projection onto the subject-under-inspection of said output of said fixed-pattern optic; and (e) a plurality of images captured of said output of said fixed-pattern optic during projection onto the subject-under-inspection are used for the image acquisition.