跟踪测距式三维坐标视觉测量系统

Distance tracking 3D coordinates vision measuring system

提出了一种跟踪测距式视觉坐标测量系统,主要由一架摄像机、一台激光测距仪、一台计算机和一支光笔组成。测量时,摄像机测量光笔上四个光反射点的方向,依据这些方向激光测距仪可跟踪捕捉到任一光反射点,并测量出某一光反射点到激光测距仪的距离,由测得的方向和距离系统可计算出光笔笔尖接触点的三维坐标。根据四点透视问题(P4P)原理建立了系统的数学模型,由于摄像机测得的距离参数的引入,使得该数学模型(P4P问题)可以线性求解,而且解具有唯一性,推导出了被测点三维坐标的求解公式。和单摄像机视觉坐标测量系统的比对实验结果表明,在Z,Y,X轴方向上的测量稳定性精度可分别提高0.366mm、0.031mm和0.011mm。

A distance measurement tracking 3D coordinates vision measuring system is proposed, it mainly consists of a CCD camera, a laser rangefinder, a computer and a light pen. When measuring, the CCD camera registers the direction of every light-reflecting point mounted on the light pen. According to these measured directions, the laser rangefinder can track and capture each light-reflecting point, and record the distance between one of the four light-reflecting points and the laser rangefinder. Using the measured directions and distance, the system can calculate the 3D coordinates of the point touched by the pen-point. Based on the perspective-four-point problem （P4P） principle, the system＇s mathematic model is established. Because of the distance parameter, this model （P4P） can be solved linearly, and its solution is unique. The 3D coordinate analytic equations of the measured point are derived. Compared with the single CCD camera coordinates measuring system, experiment results show that this system＇s measuring stability precision is 0.336mm, 0.031 mm and 0.011 mm higher than that of the former in the direction of Z, Y, X axis respectively.