提出一种双频光纤投影自动轮廓测量技术；用一分二单模光纤耦合器产生正弦光强分布的投影光栅场；将光纤一臂绕在压电陶瓷(PZT)环上，通过压电陶瓷环引入相移值；以改变出射端两光纤间的距离来改变投影光栅场的空间频率，用双频光栅技术实现复杂形面自动轮廓测量。

A novel automatic profilometry technique by dual-frequency of optical fiber projection grating is introduced. A one to two (1×2) optical fiber coupler is utilized to generate sinusoidal intensity projection grating. A piezoelectric (PZT) cylinder wrapped by one arm of the optical fiber coupler is utilized to introduce phase shift. Different frequencies of projection gratings can be got easily through adjusting the separate distance of the two projecting optical fiber ends. Three-dimension shape can be measured automatically with this technique even in the cases of true discontinuities and noise in the phase.