Generation of Non-Uniform Fringes Pattern for Optical 3D Measurement

To address the problems, like local deformation and concentrated distribution of fringes, or even overlap and interference between the fringes in the case that the pitch of the projective fringes is small and the variation range of the object surface normal direction is large, a new algorithm for the generation of non-uniform projective fringe pattern is proposed. The uniform fringe pattern is projected to the measured object, and the phase gradient of local fringe pattern in the picture captured by the camera is adjusted to a reasonable value. Then the non-uniform projective fringe pattern is generated with the principle of inverse projected-fringe technique. The simulation and experiment show that although the measurement accuracy of 50 μm can be achieved by uniform fringe pattern or non-uniform fringes, there are 7.2% missing data points by the former and only 0.24% missing data points by the latter. It is concluded that the proposed algorithm can solve the problem of serious deformation and dense distribution of the local fringes to guarantee the reliability of the measurement data. © 2017, Editorial Office of Journal of Xi'an Jiaotong University. All right reserved.