面向光学三维测量的非均匀条纹生成方法

摘要

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 nonuniform 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.%针对投影条纹间距比较小和被测表面法向处于变化范围较大的状态时局部条纹形变严重、分布密集,甚至出现条纹间重叠干涉现象,导致相位求解、条纹中心提取等方法失效的问题,提出了一种非均匀投影条纹生成算法.先利用投影均匀条纹到被测物体上,对相机采集图像中局部条纹分布密集的区域进行相位梯度调整,再运用反向条纹投影原理计算出非均匀投影条纹.对投影均匀条纹和非均匀条纹到被测物体表面进行光学三维测量,仿真和实验结果表明:当测量精度均达到50μm时,投影均匀条纹测量时有7.2％的数据点丢失,投影非均匀条纹时仅有0.24％的数据点丢失,基本上解决了局部条纹变形严重、分布密集导致点云丢失的问题,从而保证测量数据的可靠性.