针对经典两步相移算法对光强不均匀分布和物体不均匀反射率处理能力不强的问题, 分析相移量为90°的情况, 采用光强模型, 直接对光强进行数据操作, 利用三角关系, 给出了求解折叠相位相位半角的计算方法,通过高度-相位差公式得到物体的三维形貌数据, 避免了因归一化操作过程中取最值方法引起的误差.实验对比分析了经典四步相移法和两步移相法, 表明在环境光强可以忽略不计或足够小的情况下, 该方法误差范围为±0.2 mm, 结果优于经典两步相移法, 接近于测量误差最小的四步相移法.

The typical two-step phase-shifting algorithm cannot get rid of the problem in phase unwrapping processing, which is caused by the uneven distribution of intensity and the uneven reflectivity of objects. Aiming at the problem, a intensity formula, reflecting the reflectivity of the objects, is adopted, based on the analysis of 90° phase shift. The intensity data was operated directly. Then, according to the triangle theory, a algorithm was presented to get the half angle of wrapped phase. At last, three-dimensional shape information of the tested object was decoded, according to the relationship between height and difference of phase. This method avoids the errors caused by the method used to get the maximum or minimum value. The results of the proposed method are compared with those of the typical four-step phase-shifting algorithm and the two-step phase-shifting algorithm. When the surrounding intensity can be ignored or weak, its error is ±0.2 mm. It is better than resutls of typical two-step phase-shifting algorithm, close to results of accepted low-error four-step phase-shifting algorithm.