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

Table 5

Test results obtained under different shooting distances.

Test sample (cm)	Maximum error (°)	Maximum error rate (%)	Average error (°)	Average error rate (%)
20	0.79 (250)	2.5 (10)	0.27	0.29
30	0.97 (230)	3.7 (10)	0.42	0.44
40	1.63 (150)	6.6 (10)	0.79	0.82
50	2.24 (260)	8.5 (10)	1.07	1.10