I. Introduction
With the continuous expansion of the scale of power grid, the safety performance of line insulators is increasingly required. Due to the superior performance of glass insulators, the proportion of glass insulators used in the transmission network is increasing, and its quality and safety testing is particularly important. At present, manual inspection of transmission lines assisted by unmanned aerial vehicle (UAV) technology has become more and more normal[1]. A large number of images of transmission line insulators can be obtained by UAV, and it is inevitable that false detection and omission will be caused by completely relying on manual identification. The use of computer for image detection can greatly save manpower and material resources, and effectively improve the detection efficiency.