“…As one of the most important directions of DL, object detection principally solves basic vision problems, such as classification and location of various targets in images. In the past 10 years, the system of CNN is continuously improved and enriched because scholars proposed many classical models and structures, such as region-based CNN(R-CNN), Fast R-CNN, SPP, FPN, FCN, and YOLO [ 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 ]. Some of these methods have been used by later scholars.…”