I. Introduction
In the transmission line, the bolt structure plays a crucial role in maintaining the connection and stability between various hardware and fitting components and fittings. They are the transmission line's most numerous and widely dispersed component[1]. Bolt parts have been in different outdoor environments for a long time and bear the tension of connecting hardware, which often causes missing pins. And the lack of pins will lead to the unstable structure of the hardware connected by the bolts, which will cause great hidden dangers to the normal operation of the power system. To assess and remove these possible safety issues, transmission lines are being routinely inspected by UAVs. UAV inspection not only has a high level of safety and ease of operation, but it can also analyze and gather inspection data more quickly, increasing job productivity.