基于光栅预校正的三维面形测量方法

A Method of 3D Shape Measurement Based on Alignment Grating Projection

针对传统的采用发散照明的相位测量轮廓术投影到参考面上的光场产生畸变的情况,提出一种利用逆推法从参考面上的位置坐标与光栅条纹坐标分布之间的映射关系建立投影光栅模型的方法,确保校正光栅投影到参考面上的条纹满足周期性分布。通过相位-高度映射关系恢复出被测物体的面形分布。该方法无须像传统测量方法一样将相位-高度之间的映射关系以数据表形式存储在计算机中,放宽了系统测量的约束条件,简化了测量装置,并能实现高精度测量。计算机模拟和实验均证实了该方法的有效性。

We propose a new grating model building method by the inverse-deducing method using the coordinate relationship between the reference plane and fringe pattern. The method can make sure the fringe pattern projected to the reference has standard periodicity and can solve the problem of optical distortion in reference plane in traditional phase measurement profilometry produced by divergent illumination. The 3D shape of the tested object can be reconstructed with the help of phase-height mapping algorithm. The proposed method does not need to store the relationship between phase and height as the traditional method. It does not constain the 3D measurement much, simplifies the design of measurement system and has high measuring precision. Computer simulations and experiment results validate the feasibility of this method.