In three-dimensional (3D) measurement using fringe projection profilometry (FPP), noise introduced by the camera during fringe capture can cause phase errors in the reconstructed results, affecting the accuracy of the 3D measurements. The two-frequency temporal phase unwrapping method is widely used due to its high efficiency. However, the use of only two fringe patterns in this method leads to reduced noise immunity and an increased phase error. Many researchers have focused on improving the two-frequency method, but little attention has been paid to enhancing its noise immunity. In this article, we propose a novel two-frequency phase unwrapping method. Firstly, we analyze the phase errors of the traditional 4f_h + 4 fl two-frequency method and our proposed method in detail. Then, the feasibility of the proposed method has been validated through multiple experiments and simulation results. Finally, we provide solutions to the problems encountered in our proposed method. Through experiments and simulation, our proposed method reduces the phase error by 75.90% and 91.39% relative to the traditional 4f_h + 4 fl method, in metal object and gypsum board experiments, respectively. The experimental results show that our proposed method significantly improves the reliability of phase unwrapping and reduces phase errors, thus enhancing the accuracy of 3D reconstruction.

在使用条纹投影轮廓术 (FPP) 进行三维 (3D) 测量中，相机在条纹捕获过程中引入的噪声可能会导致重建结果出现相位误差，从而影响 3D 测量的准确性。双频时间相位展开方法由于其高效率而被广泛应用。然而，在该方法中仅使用两个条纹图案会导致抗噪性降低和相位误差增加。许多研究人员致力于改进二频法，但很少关注增强其抗噪性。在本文中，我们提出了一种新颖的双频相位展开方法。首先，我们详细分析了传统4 f _h  + 4  fl二频方法和我们提出的方法的相位误差。然后，通过多次实验和仿真结果验证了所提方法的可行性。最后，我们针对我们提出的方法中遇到的问题提供了解决方案。通过实验和仿真，在金属物体和石膏板实验中，我们提出的方法相对于传统的4 f _h  + 4  fl方法分别减少了75.90％和91.39％的相位误差。实验结果表明，我们提出的方法显着提高了相位展开的可靠性并减少了相位误差，从而提高了3D重建的精度。