双四步路径相移均值法

Double four-step route phase-shifting average algorithm

在光栅投影三维表面测量系统中,光学仪器的伽玛非线性和随机噪声是影响相位展开精度的两个主要因素。双三步相移法具有同时降低这两类误差的独特优势,但仍然存在非线性误差较大且相位测量精度较低两个方面的问题。针对以上问题,提出了双四步路径相移法,首先将双三步相移法中对齐平均的思想应用于四步相移法,以降低非线性误差对测量精度的影响;进而提出了相位域空间变换多频外差方法,以利用所有测量相位进行相位平均,进一步降低随机误差的影响,提高测量精度。实验结果表明,该算法能够有效地提高相位展开的精度,具有更强的适应性。

Gama nonlinearity and random noise caused by optical devices are two main phase errors on structured light projection. Double three-step phase-shifting algorithm has the unique advantage on inhabiting both of them, but there remains two drawbacks in its measuring result including higher nonlinear error and lower measuring pecision. A double four-step route phase-shifting average algorithm was proposed for resolving above questions, which applied the idea of phase-aligning average in four-step phase-shifting algorithm to lower the effect of nonlinear error, and put forward a phase average method of phase- field space transform in multi-frequency heterodyne to weaken random noise and improve meauring precision. The experimental results show that the proposed method has higher accuracy and adaptability in phase unwrapping.