用于实时三维成像的双频结构光编解码方法

对三维重建中的实时性问题进行了研究，提出一种新的结构光双频测量方法。首先，投影光栅将基频正弦图案和高频正弦图案结合在一起，并保留一张图片作为直流分量，高频图案用于得出鲁棒性较好的高频相位信息，基频图案得出基频相位，并对高频相位进行展开，共5幅图片。其次，用相应的解码方法计算每一像素点的相位，滤除噪声干扰，得到照相机与投影仪的对应关系。最后，根据相位计算出每一采样点的三维坐标，实现三维重建。实验结果表明：计算得到的相位误差的方差为5.559 110-6 rad2，扫描时间为0.156 3 s，在保证实时性的同时有相对较高的精度。对表面深度变化复杂的物体进行三维测量，验证方法的可行性。相比较于传统的双频测量方法，本方法将投影图片数量减小到5幅的同时保持了较好的精度，可应用于扫描动态物体。

Dual-frequency structured light coding and decoding method for real-time three-dimension reconstruction

In order to realize real-time three-dimensional (3D) reconstruction, this paper proposes a novel dual-frequency method for measuring the 3D surface geometry of objects. First, a group of unit-frequency sinusoidal wave patterns and a group of high-frequency sinusoidal wave patterns are combines. Then the generated patterns are projected onto the object surface and the reflected patterns distorted by the object are captured by a camera simultaneously. Second, the unit-frequency phase and high-frequency phase can be derived through the captured unit-frequency patterns and high-frequency patterns respectively. The unwrapped phase can be obtained by unwrapping the high-frequency phase by means of the unit-frequency phase which represents the correspondences between the projector and the camera, i.e., the high-frequency patterns guarantee high-quality phase and the unit-frequency patterns help to conveniently unwrap the wrapped phase generated from the high-frequency patterns. Finally, the high-quality 3D point clouds of the object can be computed using the unwrapped phase through triangulation. To confirm the validity of the proposed method, a statue is scanned and the results indicate that the variance of the phase error is 5.559 110-6 rad2 and the sweep time is 0.156 3 s. Compared with the data of the traditional methods, the proposed method reduces the number of projected patterns and keeps the accuracy of reconstructed results.