Fast recognition of characteristic targets in spatial rendezvous and docking posture measurement

In the space rendezvous and docking, real-time measurement of the position and attitude between the visual sensor on the tracking spacecraft and the characteristic target on the target spacecraft is needed, and the premise is to quickly and accurately identify the feature targets. In this paper, a fast recongnition algorithm of four concentric ring feature targets is proposed. Firstly, the algorithm uses the optimized Otsu for image segmentation. Then the contour is extracted by the connected region recognition method. Finally, according to the relationship between the circumference and the area of the circle, the circle is determined, and the least square method is used to fit the circle and extract the center of the feature circle. The experimental results show that the method can recognize feature targets accurately and quickly within 2 m distance, and the computational efficiency to the method is improved by nearly 10 times compared with the pre-optimization algorithm.