Zhang Liang, Chen Qian, Zuo Chao, Feng Shijie
Opt Express. 2020 Aug 17;28(17):24363-24378. doi: 10.1364/OE.398814.
Fringe projection profilometry (FPP) is a widely used technique for real-time three-dimensional (3D) shape measurement. However, it tends to compromise when measuring objects that have a large variation range of surface reflectivity. In this paper, we present a FPP method that can increase the dynamic range for real-time 3D measurements. First, binary fringe patterns are projected to generate grayscale sinusoidal patterns with the defocusing technique. Each pattern is then captured twice with different exposure values in one projection period. With image fusion, surfaces under appropriate exposure are retained. To improve the real-time performance of high dynamic range (HDR) 3D shape measurements, we build a binocular fringe projection profilometry system that saves the number of patterns by geometry constraint. Further, to ensure the accuracy and robustness of HDR 3D measurements, we propose a mixed phase unwrapping method that can reduce phase unwrapping errors for dense fringe patterns. Experiment results show that the proposed method can realize accurate and real-time 3D measurement for HDR scenes at 28 frames per second.
条纹投影轮廓术（FPP）是一种广泛应用于实时三维（3D）形状测量的技术。然而，在测量表面反射率变化范围较大的物体时，它往往会受到影响。在本文中，我们提出了一种FPP方法，该方法可以提高实时3D测量的动态范围。首先，通过散焦技术投射二进制条纹图案以生成灰度正弦图案。然后在一个投影周期内用不同的曝光值对每个图案进行两次捕获。通过图像融合，保留适当曝光下的表面。为了提高高动态范围（HDR）3D形状测量的实时性能，我们构建了一个双目条纹投影轮廓术系统，通过几何约束节省图案数量。此外，为了确保HDR 3D测量的准确性和鲁棒性，我们提出了一种混合相位展开方法，该方法可以减少密集条纹图案的相位展开误差。实验结果表明，该方法能够以每秒28帧的速度实现对HDR场景的准确实时3D测量。
