Gray码结合线移的结构光三维测量

3D Measurement Based on Structured Light Using a Combination of Gray Code and Line-shift Patterns

针对二值条纹的边缘扩散问题,本文提出了一种改进型线移的结构光三维测量方法。该方法根据图像像素的邻域关系和逻辑关系,采用优化预处理方法得到了条纹图像的单像素边缘;根据边缘扩散对边缘定位的影响,采用一种二值图案对称线移的方法,线移条纹以Gray码最后一幅图案的条纹中心为基准向两侧对称线移,线移条纹宽度与Gray码最小周期宽度相等、方向与Gray码条纹方向平行;采用正交投射实现了对测量视野的唯一性编码。实验结果表明,该方法对平面重构的相对误差为0.07%,耗时5.41 s,满足精度和实时性的要求。将该方法应用在混合物体的表面测量实验中,结果验证该方法对不同工件具有良好的适应性。

In order to solve the problem of edge diffusion existing in binary patterns, an improved 3D measurement method based on structured light was proposed. Edges with pixel accuracy were obtained by adopting an optimized preprocessing approach according to pixel neighborhood relation and logic relation of images. Considering the influence of edge diffusion for edge detection, a line-shift strategy was applied which translated line-shift patterns symmetrically based on the centerline of the last Gray code pattern＇s stripes. At same time, the width of line-shift stripes was equal to the minimum of Gray code stripes width and its direction was same as Gray code patterns＇. Finally, codes of the whole-field were calculated by projecting vertical and horizontal patterns respectively. Experiments show that the relative error of reconstructing a plane is 0.07% and the reconstruction time is 5.41 s, which meets the accuracy and real-time demands. Applying this method in measuring surface of mixed targets, results prove that the proposed strategy has good adaptability of different parts.