Nested circle fitting method and device for micro hole alignment

The invention discloses a nested circle fitting method and device for micro hole alignment. The method comprises the steps of: acquiring an initial image after a first hole and a second hole are preliminarily aligned, wherein the diameter of the first hole is smaller than that of the second hole; preprocessing the initial image to obtain a preprocessed image, wherein the preprocessed image comprises a first circle corresponding to the outer contour of the first hole and a second circle corresponding to the second hole, and the first circle and the second circle are nested circles; establishing a coordinate system, and fitting the first circle by using a least square method to obtain circle center coordinates of the first circle; in the coordinate system, drawing a plurality of fourth circles intersected with the second circle by using the circle center coordinates of the first circle as a circle center to obtain a constraint straight line, and calculating circle center coordinates of the second circle accordi