基于二值离焦的双目结构光三维测量方法

Binocular structured light 3D measurement method based on binary defocus

为提高光学三维测量系统的条纹投影效率和测量精度,提出使用二值离焦方法快速投影编码条纹并结合双目立体匹配算法得到视差信息。首先采用Bayer抖动技术将投射的灰度条纹转化为二值条纹,降低投影仪离焦造成对比度、景深下降的影响。然后借助多频外差方法将包裹相位展开为绝对相位,利用视差约束关系和平均误差平方和代价计算来获取最佳相位匹配点。最后经三角测量原理和双目标定获取被测物体的深度信息和三维信息。通过实验对精密小球和雕像进行测量,表明本文提出的方法测量精度和传统十二步相移测量精度接近,比传统三步相移提高了52.8%。

To improve the fringe projection efficiency and measurement accuracy of the optical 3D measurement system,a binary defocusing method is proposed to rapidly project the coded fringes and the binocular stereo matching algorithm is used to obtain the parallax information.First,the Bayer dithering technology is used to convert the projected grayscale fringes into binary fringes to reduce the effect of the projector's defocusing on the contrast and depth of field drop.Then,the wrapped phase is expanded into absolute phase by means of multi-frequency heterodyne method,disparity constraint relation and average error sum of squares cost calculation are used to obtain the best phase matching point.Finally,the depth information and three-dimensional information of the measured object are obtained through the principle of triangulation and dual-target positioning.Through experiments on precision balls and statues,it is proved that the measurement accuracy of the method proposed in this paper is close to that of the traditional twelve-step phase shift measurement,and is 52.8%higher than the traditional three-step phase shift.