台阶状面形的投影栅线法测量技术

采用光栅投影式三维轮廓术测量物体三维形貌时，当物体是台阶状物体时，物体表面的光栅条纹有阴影，导致后面的叠相还原过程无法进行。为了解决这一问题，将被测物体放在精密的旋转平台上。通过2次成像后，对2幅图像进行图像拼接，得到清晰的被光栅调制的物体图像。在图像拼接时，引入区域黑白对比度概念，区域的黑白对比度最大位置就是黑白区域的分界线。从而精确确定中间块2个边界的位置,然后进行图像拼接。最后采用双频光栅的傅里叶变换轮廓术来实现物体的三维形貌重建。结果表明：本方法简单、精度高，可以成功解决投影时具有阴影物体的三维形貌重建问题。

3-D step profilometry measurement by grating projection

The grating projection method is used for the three-dimension profilometry measurement. But disconnected phase can't be unwrapped when shadows exist in the grating stripes due to the steps on the object. In order to resolve the problem,the object is put on a precise rotary platform to achieve the clear grating-modulated image of the object by taking two images and mosaicing them together. In the image mosaic,the conception of contrast among successive regions is introduced. Where the contrast of the successive regions is the greatest,the place is regarded as the boundary of the black and white. The place of the boundary of the middle block can be accurately located and the image is mosaiced. At last,Fourier transform profilometry based on dual-frequency grating is used to realize the three-dimensional profilometry reconstruction. The result indicates that the method is simple and accurate,and can successfully solve the problem of the three-dimensional profilometry reconstruction of the object with steps.