光栅投影测量系统三维形貌拼接技术研究

针对尺寸较大或型面复杂的被测物形貌的测量,提出了一种基于投影仪投射标记点和全局控制点的三维形貌拼接方案。方案充分利用光栅投影测量系统的优势,以拼接相机坐标系为中介,将被测物表面在投影系统视觉传感器坐标系下的多视点云坐标转换到全局坐标系下,实现了将投影系统视觉传感器在不同位置、不同角度的测量数据统一到全局坐标系,完成拼接。该方案避免了人工标记点的粘贴,保持了被测物表面的原有形貌,提高了测量效率,同时克服了基于相邻图像重叠拼接中的误差累积问题。此方案方法操作简单,原理可行,精度可满足要求。实验结果表明:拼接的X,Y,Z坐标均方根误差分别为:0.056 mm、0.023 mm、0.165 mm,测量系统的绝对误差为0.33 mm。

The research of 3D morphology splicing techniques of grating projection measuring system

To solve the morphology measurement of objects which are large in size or complex in surface, a 3D morphology splicing scheme based on projection markers and global controlling points is proposed. The scheme makes full use of the advantages of grating projection measuring system. Using splicing camera coordinate system as the intermediary, multi-view point cloud coordinates of measured surfaces in the projection system vision sensor coordinate system are converted to the global coordinate system. Measurement data which are measured by the projection system vision sensor in different positions and different angles are unified into the global coordinate system so that the morphology splicing can be accomplished. This scheme avoids pasting the artificial markers and maintains the original morphology of the surface of the measured objects. Measuring efficiency is improved and the error accumulation problem based on the overlap splicing of adjacent images is overcome. The method of this scheme is simple and practical. The accuracy can also meet the requirements. The experimental results show that the splicing RMS errors of X, Y, Z coordinate are 0.056mm, 0.023mm and 0.165mm. The absolute error of the measurement system is 0.33 mm.