Patent ID: 6154279
Filing Date: 2000-11-28
Classification: G01B

Abstract:
A method of determining an orientation of a camera used to observe a countersunk hole, the method comprising the steps of:a) electronically measuring coordinates of a plurality of points on a countersunk hole, the countersunk hole having an axis and an apex, and storing said coordinates in a memory of a computer, said coordinates of each of said plurality of points being designated by (x.sub.i, y.sub.i, z.sub.i),b) deriving two distinct expressions for a radius of the countersunk hole corresponding to each of said points, wherein said expressions are functions of x.sub.0, y.sub.0, z.sub.0, x.sub.1, y.sub.1, and .phi., where (x.sub.0, y.sub.0, z.sub.0) is the apex of the countersunk hole, (x.sub.1, y.sub.1, z.sub.1) is a point at which the axis of the countersunk hole intersects a reference plane z=z.sub.1 =0, and .phi. is an angle between the axis of the countersunk hole and a line connecting the apex of the countersunk hole and one of the points (x.sub.i, y.sub.i, z.sub.i),c) selecting values of parameters x.sub.0, y.sub.0, z.sub.0, x.sub.1, y.sub.1, and .phi. so as to minimize an error function comprising a comparison of said two distinct expressions,d) determining an orientation of vector V defined byV=(x.sub.1 -x.sub.0)i+(y.sub.1 -y.sub.0)j+(z.sub.1 -z.sub.0)kwherein the orientation of V corresponds to an orientation of the camera with respect to the countersunk hole.