基于希尔伯特变换的三频三步相移结构光三维重建方法

Three-Frequency Three-Step Phase-Shift Structured Light 3D Reconstruction Method Based on Hilbert Transform

摘要: 在光学三维重建技术中，当投影仪以恒定的投影速率工作时，减少投影条纹图案的数量是减少投影时间的有效方法。为了提高物体形貌的三维重建的速度，我们提出了基于希尔伯特变换的三频三步相移结构光三维重建方法。我们对最高频率的条纹投影三个条纹图案，条纹之间的相移设计为3π/2，其余两个频率的条纹分别投影一个条纹图案。利用其余两个频率的投影的条纹和背景光强图像获取余弦分量，希尔伯特变换将余弦分量与冲击响应进行卷积，在频率和幅度保持不变的前提下将相位移动π/2。为了提高该方法的准确性和鲁棒性，我们采用了三频外差法来进行相位展开。实验结果表明：该方法在对高精度标准球重建时精度为0.0399 mm，重建精度较高。投影条纹图片由传统的9幅缩减到了5幅，提高了投影效率。

Abstract: In optical 3D reconstruction techniques, when the projector works at a constant projection rate, reducing the number of projected fringe patterns is an effective way to reduce the projection time. In order to improve the speed of 3D reconstruction of object morphology, we propose a three-frequency, three-step phase-shift structured optical 3D reconstruction method based on Hil-bert transform. We project three fringe patterns for the highest frequency fringe, and the phase shift between the fringes is designed to be 3π/2, and one fringe pattern is projected for each of the remaining two frequencies. The cosine components are obtained using the projected fringes of the remaining two frequencies and the background light intensity image, and the Hilbert transform convolves the cosine components with the shock response to shift the phase by π/2 while keeping the frequency and amplitude constant to improve the accuracy and robustness of the method, we use the three-frequency outlier method to perform the phase expansion. The experimental results show that the method has a high reconstruction accuracy of 0.0399 mm when reconstructing the high-precision standard sphere. The projected fringe images are reduced from the traditional 9 to 5, which improves the projection efficiency.