为了实现大型自由曲面的三维面型测量,提出了采用光学定位跟踪技术的数据拼接方法。平面靶标作为中介,固定在测量系统上,靶标上的特征点在测量坐标系中的坐标通过中介坐标转换法获得。利用双目立体视觉构建跟踪定位系统,并以跟踪坐标系为全局坐标系,获取平面靶标上特征点的三维全局坐标,求得测量坐标系到全局坐标系的转换矩阵。将测量传感器在不同位置下所测的各子区域的三维数据统一到全局坐标系下,完成大型自由曲面的全局测量。实验结果表明:单次测量精度为0.11mm;对10cm×10cm的平面靶标上100个点进行两次测量,拼接均方误差为0.34mm。该方法操作简单、可行,并可满足要求。
In order to realize 3D shape acquisition for large free surface, a data registration method using optical location tracking technology was proposed. A planar target was fixed on the measurement system as the intermediate, the coordinates of some feature points provided by the target in the measurement coordinate system were obtained by a intermediary coordinate transformation method. A location tracking system was constituted by binocular stereo vision, then,the tracking coordinate frame was used as the global coordinate frame to obtain 3D global coordinate of feature points on planar target to derive the transformation matrix from the measurement coordinate frame to the global coordi- nate frame. All the 3D data of sub-areas obtained by the measurement sensor were unified in the global coordinate frame, and the global measurement for a large object was accomplished. The registration experiment was conducted using 100 feature points on the planar target, and the results show that the single measurement precision is 0. 11 mm, and the RMS error of 3D data registration is less than 0.34 mm. The presented method is simple and flexible, and can satisfy the precision requirements.