基于圆形条纹投影的相位测量轮廓术研究

Absolute Phase Calculation of Circular Fringe Projection in PMP

编码的圆形正弦条纹在圆心具有零相位,该点可以作为后续相位计算和展开的参考。但是圆形条纹提供的载频相位具有非线性特点,当其用于三维面形测量时,如果圆心在物面上,获取物面高度信息的方法与投影单频直条纹的情况不同。研究基于圆形条纹投影的相移轮廓术,讨论了物面高度引起的图像点坐标的位移量和绝对相位的计算方法,并完成相应的误差分析。对3.5 mm平面测量误差的标准差为0.019 mm。计算机模拟和实验验证了该方法能直接得到离面物体的绝对相位,用于重建物体的三维面形。

The coded circular fringe has zero-phase in the center of fringe image,which can be used as a reference for the subsequent calculation of absolute phase and unwrapping.However,the carrier frequency phase provided by circular fringes is nonlinear.When it is used to measure three-dimensional surface shape,the method for obtaining object height information is different from that of projecting single frequency straight fringes.The calculation method of object height information in phase-shifting profilometry are studied based on circular fringe projection.The calculation method of coordinate displacement is discussed caused by height in detail.The corresponding error analysis is completed.Computer simulation and experimental verification show that the method can directly obtain the absolute phase of out of plane object,which can be used to reconstruct the three-dimensional shape of the object.