Detection of the Bolt Loosening Angle through Semantic Key Point Extraction Detection by Using an Hourglass Network

Table 2

NEs obtained under manual and automatic labeling.

Keypoint	P1	P2	P3	P4	P5	P6	Average
Manual label (10^−3)	7.98	9.69	10.94	8.91	9.69	10.46	9.61
Auto label (10^−3)	7.70	8.71	10.22	7.88	9.41	8.85	8.79
NEreduction (%)	3.64	11.27	7.06	13.04	3.03	18.10	9.28