A positioning method based on image geometric moment and center of gravity of material and convex hull form vector line angle

when the material is irregular shape

calculate geometric moment of input area to get ellipse

using the zero and 1 order of geometric moment to calculate the center of gravity of the material area

and then compute the point which has the longest distance from center of gravity to regional profile

through the longest point

give positive direction to originally no directional elliptic

rotation angle is the intersection angle between long axis in the positive direction and horizontal coordinate axis.When the material is a regular symmetric figure

the rotation angle of the material is calculated by calculating the intersection angle between the vector line and the horizontal axis formed by the center of gravity of the input region and the center of gravity of the convex hull of the region.Theoretical analysis and experimental results show that the positioning method is simple and flexible

and the positioning precision and speed are within the expected range.