Ambiguity caused by a wrapped phase is an intrinsic problem in fringe projection-based 3D shape measurement. Among traditional methods for avoiding phase ambiguity, spatial phase unwrapping is sensitive to sensor noise and depth discontinuity, and temporal phase unwrapping requires additional encoding information that leads to an increase of image sequence acquisition time or a reduction of fringe contrast. Here, to the best of our knowledge, we report a novel method of absolute phase unwrapping based on light field imaging. In a recorded light field under structured illumination, i.e., a structured light field, a wrapped phase-encoded field can be retrieved and resampled in diverse image planes associated with several possible fringe orders in a measurement volume. Then, by leveraging phase consistency constraint in the resampled wrapped phase-encoded field, correct fringe orders can be determined to unwrap the wrapped phase without any additional encoding information. Experimental results demonstrated that the proposed method was suitable for accurate and robust absolute phase unwrapping.

中文翻译：

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基于光场的绝对相位展开

由包裹相位引起的歧义性是基于条纹投影的3D形状测量中的固有问题。在避免相位模糊的传统方法中，空间相位展开对传感器噪声和深度不连续敏感，而时间相位展开则需要其他编码信息，这会导致图像序列获取时间增加或条纹对比度降低。在此，据我们所知，我们报告了一种基于光场成像的绝对相位展开的新方法。在结构化照明下的记录光场（即结构化光场）中，可以在与测量体积中几个可能的条纹阶次相关联的不同图像平面中检索包裹相位编码场并对其重新采样。然后，通过利用重新采样的包裹相位编码字段中的相位一致性约束，可以确定正确的条纹顺序来展开包裹相位，而无需任何其他编码信息。实验结果表明，该方法适用于准确，鲁棒的绝对相位解缠。