平行光干涉投影三维形貌恢复方法

传统傅立叶变换轮廓术多采用散光斜式投影，需要满足4个约束条件才能得到较为准确的相位与高度映射关系，并且散光投影带来的相位非线性二次项误差也会降低形貌恢复精度。为了能在欠约束条件下减少相位非线性误差的影响，建立了基于平行光干涉投影下的普适模型。平行光干涉投影下的参考平面相位沿着x轴呈线性变化，相位分布较散光或倾斜式投影更具准确性。对比分析了散光及平行光投影下被测物体的恢复情况，实验结果表明，新模型在欠约束条件下，具有较高的灵活性和可操作性，恢复精度良好，相对误差为1.1%。

Three dimensional shape restoration method with parallellight interference projection

In traditional Fourier transform profilometry, the astigmatism projection is used and 4 constraints are needed to obtain accurate mapping relationship between phase and height. Moreover, the phase nonlinear quadratic error caused by astigmatic projection can also reduce the topographic recovery accuracy. In order to reduce the influence of phase nonlinearity in less restricted conditions, a universal model based on parallel optical interference projection was established. The reference plane phase under the parallel optical interference projection changes linearly along x-axis, the phase distribution is more accurate than the astigmatic projection or oblique projection. The restoration of the measured object under astigmatism and parallel light projection was compared and analyzed. The experimental results show that the new model has high flexibility and operability under less restricted conditions, and the recovery accuracy is good, the relative error is 1.1%.