Method for acquiring disc contour on line by using eddy current automatic detection system

The invention belongs to the field of nondestructive testing, and relates to a method for acquiring a disc contour on line by using an eddy current automatic detection system. The method is characterized in that a metal straight rod, a direct-current power supply and an indicating element are additionally arranged on the basis of a mechanical scanner, a rotary table and control software of a disc eddy current automatic detection system to form a disc ring contour measuring system. The measuring method is summarized as follows: a mechanical scanner drives a metal straight rod to move, the radial overall dimension of a disc concentrically clamped on the surface of a rotary table is measured, the coordinate value of the mechanical scanner when the top end of a measuring head is just in contact with a workpiece is recorded, and coordinate transformation and graphic processing are carried out by combining information such as the working angle of the metal straight rod, the contact position of the metal straight ro