基于线结构光的柴油机缸盖三维形貌测量

Three-dimensional Data Measurement of Engine Cylinder Head Blank Based on Line Structured Light

为了获取某种型号内燃机工件的三维形貌数据,设计了线结构光非接触方式的移动扫描测量系统。探索出了以虚拟双目立体视觉原理为理论基础的相机光心平移轨迹所在直线的方向余弦标定的实现方法,从而确定由系统中各局部坐标系变换到系统全局坐标系的旋转矩阵R和平移向量T,进而求出系统中各个局部坐标系原点在系统全局坐标系下的坐标值,最后得到相机光心移动轨迹所在直线的方向余弦。探索出利用相机的移动距离及方向余弦将局部坐标系数据转换至全局坐标系的计算方法,扫描获取了某种型号柴油机缸盖的三维形貌点云数据,在此基础上设计算法从中提取出气道口的中心坐标,测量精度较高。采用逆向工程软件对工件进行了表面重构,结果与实际表面特征信息吻合良好。

In order to obtain three-dimensional data of engine cylinder head blank, a passive line structured light canning measurement system is designed. Calibration of the direction cosine of the movement of camera optical center is given based on principle of virtual binocular stereo vision. Stereo vision system consists of a single camera moving along the one-dimensional rail, which gives Rotation matrix R and Translation vector T between local coordinate system and global coordinate system. And then the origin of local coordinate system is conversion to the global coordinate system so that the line of movement of camera along the rail is fitted and its direction cosine is calculated. Three-dimensional topography of a certain cylinder head is scanned and the cloud data on this topography is obtained, from which the data of Intake port center coordinates is extracted. Finally, the three-dimensional data is dealt with reverse engineering software and surface reconstruction works well.