Mandapalli Jagadeesh Kumar, Ravi Vaishnavi, Gorthi Sai Siva, Gorthi Subrahmanyam, Gorthi Rama Krishna
J Opt Soc Am A Opt Image Sci Vis. 2021 Oct 1;38(10):1471-1482. doi: 10.1364/JOSAA.430981.
Fringe projection profilometry (FPP) is a widely used non-contact optical method for 3D profiling of objects. The commonly used linear fringe pattern in FPP has periodic intensity variations along the lateral direction. As a result, the linear fringe pattern used in FPP cannot uniquely represent the lateral shift induced by the objects having surface discontinuities. Thus, unambiguous surface profiling of objects, especially with surface discontinuities, using a single linear fringe image having a single fringe frequency, is unfeasible. This paper proposes using a radially symmetric circular fringe pattern as the structured light pattern for accurate unambiguous surface profiling of sudden height-discontinuous objects. To the best of our knowledge, this is the only method that can reconstruct discontinuous height profiles with the help of a single fringe image having a single frequency. The performance of the proposed algorithm is evaluated on several synthetic and real objects having smooth variations and discontinuities. Compared to the well-known fringe projection methods, the results depict that for a tolerable range of error, the proposed method can be applied for the reconstruction of objects with 4 times higher dynamic range and even at much lower fringe frequencies.
条纹投影轮廓术（FPP）是一种广泛应用于物体三维轮廓测量的非接触光学方法。FPP中常用的线性条纹图案在横向具有周期性强度变化。因此，FPP中使用的线性条纹图案无法唯一表示由具有表面不连续的物体引起的横向位移。因此，使用具有单一条纹频率的单个线性条纹图像对物体进行明确的表面轮廓测量，尤其是对于具有表面不连续的物体，是不可行的。本文提出使用径向对称的圆形条纹图案作为结构光图案，用于对高度突然不连续的物体进行精确的明确表面轮廓测量。据我们所知，这是唯一一种能够借助具有单一频率的单个条纹图像重建不连续高度轮廓的方法。在所提出算法的性能在几个具有平滑变化和不连续的合成物体和真实物体上进行了评估。与著名的条纹投影方法相比，结果表明，在可容忍的误差范围内，所提出的方法可应用于动态范围高4倍甚至条纹频率低得多的物体的重建。
