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

Figure 4

Process for calculating bolt loosening angle. (a) Determine the coordinates of each corner point and center point. (b) Calculate the angle between each corner point and the center point. (c) Calculate the angle between each corner point and the center point after loosening. (d) Calculate loose angle.

(a)

(b)

(c)

(d)