For the insulators, M-YOLO v3, D-YOLO v3, and M-YOLO v4 each detected no more than two insulators, indicating their poor detection performance. D-YOLO v4 correctly detected the majority of the insulators, with the exception of those at positions (4) and (9). In contrast, YOLO v5, Pi-FT, and ours Pi-Index were able to accurately detect all of the insulators. These results show that Pi-Index is capable of achieving high detection performance under labeled conditions.
Furthermore, we compared the details in the detection results of YOLO v5, Pi-FT, and Pi-Index. Firstly, the detection results at positions (3)-(5) indicate that both Pi-FT and Pi-Index were significantly more accurate in locating insulators than YOLO v5. Subsequently, Pi-Index also identified the unannotated insulator at position (7). This further demonstrated the effectiveness of the proposed method when applied to unannotated data. Although D-YOLO v4 was able to detect two unannotated insulators, its failure to detect some annotated insulators resulted in an overall detection performance that was inferior to that of the Pi-Index.