相位展开中基于调制度轮廓线的极点连接算法

在相位测量型光学3维传感技术中,为了正确恢复物体的真实相位,采用了一种基于调制度轮廓线连接极点的相位展开算法。该算法将调制度分布图与分支阻断法相结合,利用图像增强技术中拉普拉斯算子检测边缘,从被测物体调制度分布中提取物体的轮廓线,用于指导极点的连接和截断线的设置,最后结合菱形算法快速展开被测物体的截断相位,能够得到较为真实的相位展开结果。实验结果表明,新方法结合了调制度分布图展开相位可靠和分支阻断法计算时速快的优点。在面形存在陡变和凹陷的复杂情况下,新算法甚至比可靠度排序法更能够有效地恢复出物体的真实相位,保证了测量的精度,而且运算速度比可靠度排序算法快了3倍。

Novel branch cuts ' placement based on the outline of the modulation in phase unwrapping

When using triangular method to measure a complex shape in optical three-dimensional scan technologies, the fringe pattern will have the problem of shadows, fringe discontinuities and undersampling, resulted the residues appearance. It is difficult to restore the nature phase of the measured objects. A new method has been put forward which connects the residue pairs to branch cuts based on the outline of modulation of the measured object. It employs Laplacian Edge Detection to extract the outline of modulation, which will be used to guide the branch cuts setting. Then, combined with Diamond phase-unwrapping algorithm, the wrapped phase of the measured object can be restored accurately. The experiment on a cat model makes it clear that under the condition of a steep-shape object be measured, this new method can effectively remain the accuracy of measurement and speedily restore the nature phase of the tested objects. It saves more time than that of reliability-guided phase unwrapping algorithm based on sorting, only about 33% of reliability-guided algorithm time consumption is needed to execute this presented method.