基于正交光栅投影的快速调制度测量轮廓术

Fast Modulation Measurement Profilometry Technology Based on Cross Grating Projection

在共轴光学测量系统中,将水平光栅与竖直光栅沿着光轴方向相距一定距离垂直放置,被测物体放置在两个光栅成像面之间.利用同光轴方向放置的CCD采集一帧正交光栅像,进行傅里叶变换、滤波和逆傅里叶变换操作,分别得到对应水平条纹分量和竖直条纹分量的调制度图,通过计算其调制度比,实现对复杂物体的快速三维面形测量.在几何光学近似条件下,给出两个光栅投影像的光强表达式,讨论了水平光栅与竖直光栅间距和投影镜头光圈大小对测量结果的影响.对标准平面和复杂物体三维面形的快速测量结果表明,该方法能快速有效地测量恢复物体的三维信息.

In the coaxial optical measurement system,a horizontal grating and a vertical grating were vertically placed in the light path along the optical axis separately,and the tested object was placed just within the image planes of the two gratings.The orthogonal grating fringe pattern is captured by CCD camera which is installed in the same optical axis.The modulation distributions corresponding to the vertical and horizontal components of the cross grating pattern were obtained by Fourier transform,filtering and inverse Fourier transform operation.The profile of the tested object was reconstructed from ratio of the two modulations.Under the condition of geometrical optics approximation,the intensity expressions of the image of the two grating projection were given.The influence of the distance of two gratings and aperture size of projection lens on the measurement result was discussed.A standard plane and a complex object were measured by this methods.Experiment results show that the method can quickly and effectively restore the 3D information of the object.