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

Table 6

Test results obtained under different shooting angles.

Test sample	Maximum error (°)	Maximum error rate (%)	Average error (°)	Average error rate (%)
0° of tilt	1.79 (230)	5.50 (10)	0.82	0.82
10° of tilt	2.34 (350)	6.00 (10)	0.90	0.87
20° of tilt	2.66 (160)	6.44 (10)	1.17	1.16
30° of tilt	3.08 (340)	8.00 (10)	1.30	1.40