The model for a laser distance tracking 3D coordinates vision measuring system

A laser distance 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 n-point problem principle, the system mathematic model is established. By introducing the distance parameter, this model can be solved linearly, and its solution is unique. On the basis of the redundancy technology, the 3D coordinates analytic equations of the measured point and its solving method are given. Compared with the single CCD camera coordinates measuring system, experiment result shows that this system measuring stability precision is 0.336mm, 0.031mm and 0.011mm higher than that of the former in the direction of Z, Y, X axis respectively.