转台中心轴线标定误差分析与修正

提出一种标定球和几何变换相结合的方法修正三维激光数字化系统中转台中心轴线的标定误差.该方法首先用8个不同旋转位置的标定球球心计算转台中心轴线,然后利用几何变换将不同位置的球心绕转台中心轴线旋转到零度位置,并计算与初始位置球心的偏差,依据不同位置球心旋转复位的偏差采用几何逆变换推导出转轴偏心的修正公式.在自行设计的三维激光线扫描测量平台上数据旋转拼合精度提高到0.07?mm,实现了多视旋转测量的数据点云在线自动拼合.与以前的方法相比,设计的转轴标定误差修正方法简单、高效,在其它安装转台的测量系统中同样适用.

Analysis and modification of turntable’s axis calibration

A new method using the standard ball and geometrical transform technique was proposed to modify the calibration error of the turntable’s axis in three dimensional laser digitizing system. The turntable’s axis was counted by the center of the standard ball at 8 different rotation angles, The center of different positions was revolved to the zero degree position by geometrical transform, the deviations between the center of different positions and the center of the ball at the zero degree position was counted. Through reverse geometrical transform, the modified format of the eccentricity was deduced from the coordinate deviation caused by turning on the eccentricity. The registration accuracy was raised to 0.07mm by self-design three dimensional laser scan measurement platform, the multiple views have been integrated automatically on line. Compared with the previous methods, the new method is simple and efficient, and can be used in other measuring system with a turntable.