Qian Jiaming, Tao Tianyang, Feng Shijie, Chen Qian, Zuo Chao
Opt Express. 2019 Feb 4;27(3):2713-2731. doi: 10.1364/OE.27.002713.
Fourier-transform profilometry (FTP) and phase-shifting profilometry (PSP) are two mainstream fringe projection techniques widely used for three-dimensional (3D) shape measurement. The former is well known for its single-shot nature and the latter for its higher measurement resolution and precision. However, when it comes to measuring the dynamic objects, neither approach is able to produce high-resolution, high-accuracy measurement results that are free from any depth ambiguities and motion-related artifacts. Furthermore, for scenes consisting of both static and dynamic objects, a trade-off between measurement precision and efficiency has to be made, suggesting that using a single approach can yield only suboptimal results. To this end, we propose a novel hybrid Fourier-transform phase-shifting profilometry method to integrate the advantages of both approaches. The motion vulnerability of multi-shot PSP can be overcome, or at least significantly alleviated, through the combination of single-shot FTP, while the high accuracy of PSP can also be preserved when the object is motionless. We design a phase-based, pixel-wise motion detection strategy that can accurately outline the moving object regions from their motionless counterparts. The final measurement result is obtained by fusing the determined regions where the PSP or FTP is applied correspondingly. To validate the proposed hybrid approach, we develop a real-time 3D shape measurement system for measuring multiple isolated moving objects. Experimental results demonstrate that our method achieves significantly higher precision and better robustness compared with conventional approaches where PSP or FTP is applied separately.
傅里叶变换轮廓术（FTP）和相移轮廓术（PSP）是广泛用于三维（3D）形状测量的两种主流条纹投影技术。前者以其单次测量特性而闻名，后者则以其更高的测量分辨率和精度而著称。然而，在测量动态物体时，这两种方法都无法产生高分辨率、高精度且无任何深度模糊和运动相关伪影的测量结果。此外，对于由静态和动态物体组成的场景，必须在测量精度和效率之间进行权衡，这表明使用单一方法只能产生次优结果。为此，我们提出了一种新颖的混合傅里叶变换相移轮廓术方法，以整合这两种方法的优点。通过单次FTP的结合，可以克服或至少显著减轻多次拍摄PSP的运动脆弱性，同时当物体静止时也可以保留PSP的高精度。我们设计了一种基于相位的逐像素运动检测策略，该策略可以从静止的对应物中准确勾勒出运动物体区域。最终的测量结果是通过融合相应应用PSP或FTP的确定区域而获得的。为了验证所提出的混合方法，我们开发了一个用于测量多个孤立运动物体的实时3D形状测量系统。实验结果表明，与单独应用PSP或FTP的传统方法相比，我们的方法具有显著更高的精度和更好的鲁棒性。
