“…Among them, a lot of studies [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 ] have focused on the inspection of solder joints, which is both important and challenging. Researchers have proposed a number of methods for solder joint inspection that use neural networks [ 1 , 2 ], fuzzy rules [ 3 ], Boolean rules [ 4 ], deep learning [ 5 ], support vector machines [ 6 ], decision trees [ 7 ], principle component analysis [ 8 ], modal analysis [ 9 ], etc. Component placement inspection is another significant and challenging problem, and it is the basis of other PCB inspections, such as the inspection of solder joints.…”