Pose measurement of large non-cooperative target using line structured light vision

In final approach of rendezvous between a space robot and a large non-cooperative target, a monocular camera of the space robot can not observe a complete feature image of the target to determine relative position and attitude. To overcome this problem, a line structured light is introduced to aid measurement. A partial rectangular framework of the target is chosen as measurement object. Firstly, a measurement model is built and four measurement coordinate systems are presented. Secondly, according to camera projection constraints on the partial rectangular framework and the line structured light, four feature points are calculated in the camera coordinate system. Thirdly, using the four feature points, transform matrix between camera coordinate system and target coordinate system is computed. Lastly, the relative position and attitude of the partial rectangular framework is derived from the transform matrix. Numerical simulations are studied to verify the method under different input errors and calibration errors. The results show that this method is effective.