Rotating-prism-based tracking imaging for target-locking acquisition using second-order boresight adjustment strategy

Tracking imaging systems capable of target-locking acquisition have broad application prospects in military reconnaissance, autonomous navigation, and security monitoring. In this paper, a flexible and compact tracking imaging model with precise beam pointing is built consisting of a camera coaxially embedded with rotating double prisms. A second-order boresight adjustment strategy including a fast approach stage and an accurate adjustment stage is proposed to accomplish high-efficiency and precision optical axis pointing. The fast approach stage enables the boresight to quickly approach the object of interest (OOI) based on imaging feedback, reducing time consumption and improving efficiency. On the other hand, an accurate adjustment stage using azimuth-pitch coupling control further precisely alters the boresight to improve tracking accuracy. Simulation analysis for tracking range and blind area is performed to guide system design. Compared with the coarse-fine coupling method, the proposed method provides less and more stable time consumption even if large tracking distance. Experimental results demonstrate that our architecture enables better than pixel-level tracking for a static target and dynamic target tracking with better than 30 pixels, balances efficiency and accuracy, expands the imaging range without camera motion, and gets rid of the dependence on prior distance information, accurate system parameters, and complex system calibration.