Recognizing methods of circular holes

Abstract

Positions of overlapping first and second circular holes of respective first and second objects are detected, the first and second objects to be screwed together by a robotic screwing mechanism. An upper surface of the first object is viewed with an image pick-up device to obtain an image of the first circular hole and a partial image of the second circular hole which overlaps the image of the first circular hole. Two maximally spaced-apart boundary points from among the boundary points along an outer periphery of the partial image are detected. First and second circles within an image frame are defined which include the two maximally spaced-apart boundary points and which have respective centers of gravity which are symmetric to each other relative to a line segment connecting the maximally spaced-apart boundary points. The positions of the first and second circular holes are detected based on the defined first and second circles within the image frame.