为了加强相位展开过程的准确性和鲁棒性, 提出了一种新颖的梯形相位展开算法。该算法结合了灰度和相位两种编码方式进行相位展开。基于灰度的相位展开可以通过投射不同的灰度确定不同的等级, 但是当条纹周期非常小, 相应的灰度差异也非常小, 使相位展开出现错误。相位展开具有很强的鲁棒性, 但本身计算量很大。与传统算法相比, 该算法设计了两类模式快速地恢复绝对相位。第一类模式是基于灰度信息对全局调制光栅进行分割, 第二类模式是基于相位进行编码, 同时在第一模式中对全局调制光栅进行更加细致的分级, 第二类模式变化的周期与包裹相位的截断周期一致。因为颜色能够简单而且准确地确定边界, 同时相位有很好的鲁棒性, 因此, 能够准确地恢复绝对相位。实验结果表明: 提出的算法能够准确地确定包裹相位的等级, 而且能够快速地得到物体表面的三维信息。

In order to increase the accuracy and robustness of phase unwrapping, a novel stair phase unwrapping algorithm was proposed. This algorithm combined the gray and phase coding to unwrap the phase. The algorithm based on gray can project different gray intensities to determine different levels. However, when the period was small, there was little difference between intensities which will generate phase errors. Phase unwrapping based on phase had great robustness but it occupied the computation. Compared with traditional method, the creative point of this method was that it designed two encoding methods for phase unwrapping. The first type of pattern was based on grey information that separated the global modulation grating. The second type of pattern was based on phase coding. The experimental results show that the algorithm can determine the level of the wrapped phase accurately and the 3D information can be obtained quickly.