Nested circle fitting method for achieving centering of wire electrode and oil spray hole

The invention discloses a nested circle fitting method for achieving centering of two small holes having different apertures. The method comprises the following steps: S1, providing a first hole and a second hole which has an aperture different from an aperture of the first hole, and performing primary centering on the first hole and the second hole through adoption of a small hole centering device; S2, obtaining an image of the primary centering of the first and second holes, wherein the first hole in the image corresponds to a first circle, and the second hole corresponds to a second circle, performing grayscale and binary processing on the image to obtain a binary image, and performing edge extraction on the binary image to obtain a first image; S3, performing de-noising processing on the first image; S4 establishing a coordinate system, fitting the first circle through utilization of a least square method, and determining a coordinate position of the center of the first circle; S5, determining a coordinat