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 1×10-6 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.%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 1×10-6 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.
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