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

Table 7

Test results obtained under different luminance levels.

Test sample	Maximum error (°)	Maximum error rate (%)	Average error (°)	Average error rate (%)
Luminance70	1.40 (270)	3.50 (10)	0.41	0.49
Luminance50	1.25 (230)	4.70 (10)	0.45	0.50
Luminance30	1.42 (230)	5.20 (10)	0.46	0.55
Luminance10	1.85 (300)	6.00 (10)	0.85	0.84