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

Table 4

Absolute and percentage errors in the bolt loosening angle when using the proposed method.

Calculated value (°)	Actual value (°)	Difference value (°)	Error rate (%)
0.32	0.5	0.18	36
1.39	1	0.39	39
2.38	2	0.38	19
3.58	4	0.42	10.5